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Combining ability of nine sunflower inbreds (four cytoplasmic male sterile lines and five restorers) was tested in line x tester mating design. The material including parents and cross combinations were evaluated for nine agro-biochemical parameters. The inbreds viz., 67A and 47R were identified as good general combiners for seed yield and oil yield, 88A, 89A, 47R and GMU 1080 were identified as good general combiners for oil content and 67A, 179R and GMU 1080 exhibited good general combining ability for early maturity. Similarly, highest significant positive specific combining ability effects for seed yield were observed for crosses 38A x 179R followed by 89A x 179R and 88A x 159R. On the basis of positive significant SCA effects for oil percent the crosses 67A x GMU 1080, 89A x 159R and 88A x 150R were found to be superior. All the traits exhibited non-additive gene action and the proportional contribution to variability was maximum by crosses except for seed yield where lines contributed more towards variability. The crosses 67A x 47R, 89A x 179R, 38A x 179R and 88A x 150R recorded maximum average heterosis for seed and oil yield and the cross combinations 67A x 47R, 88A x 150R and 67A x GMU 1080 revealed maximum heterosis against better parent also for the above traits.

Combining ability of nine sunflower inbreds (four cytoplasmic male sterile lines and five restorers) was tested in line x tester mating design. The material including parents and cross combinations were evaluated for nine agro-biochemical parameters. The inbreds viz., 67A and 47R were identified as good general combiners for seed yield and oil yield, 88A, 89A, 47R and GMU 1080 were identified as good general combiners for oil content and 67A, 179R and GMU 1080 exhibited good general combining ability for early maturity. Similarly, highest significant positive specific combining ability effects for seed yield were observed for crosses 38A x 179R followed by 89A x 179R and 88A x 159R. On the basis of positive significant SCA effects for oil percent the crosses 67A x GMU 1080, 89A x 159R and 88A x 150R were found to be superior. All the traits exhibited non-additive gene action and the proportional contribution to variability was maximum by crosses except for seed yield where lines contributed more towards variability. The crosses 67A x 47R, 89A x 179R, 38A x 179R and 88A x 150R recorded maximum average heterosis for seed and oil yield and the cross combinations 67A x 47R, 88A x 150R and 67A x GMU 1080 revealed maximum heterosis against better parent also for the above traits. [ABSTRACT FROM AUTHOR]

Combining ability, along with heterosis was elucidated for nine yield attributing and 10 grain quality traits in a set of 40 rice hybrid combinations derived from 13 parents using Line × Tester mating approach. The analysis of combining ability unveiled significant GCA and SCA variances, highlighting the importance of both additive and non-additive genetic components. The ratio of dominant genetic variance to additive genetic variance exceeded unity, indicating the prevalence of non-additive gene action in governing the inheritance of all examined traits. The parental line CO 55 and the testers IC 457996 and IC 208262 were recognized as good combiners for the majority of yield-related and grain-quality traits. Regarding per se performance, heterosis, and sca effects, the crosses CO 55 × IC 457996, ADT 54 × IC 115439 and ADT 54 × IC 115439 were found promising. Consequently, these combinations could be exploited for recombination breeding aimed at developing early maturing, high-yielding fine-grain rice varieties with market acceptance.

Combining ability, along with heterosis was elucidated for nine yield attributing and 10 grain quality traits in a set of 40 rice hybrid combinations derived from 13 parents using Line x Tester mating approach. The analysis of combining ability unveiled significant GCA and SCA variances, highlighting the importance of both additive and non-additive genetic components. The ratio of dominant genetic variance to additive genetic variance exceeded unity, indicating the prevalence of non-additive gene action in governing the inheritance of all examined traits. The parental line CO 55 and the testers IC 457996 and IC 208262 were recognized as good combiners for the majority of yield-related and grain-quality traits. Regarding per se performance, heterosis, and sca effects, the crosses CO 55 x IC 457996 and ADT 54 x IC 115439 were found promising. Consequently, these combinations could be exploited for recombination breeding aimed at developing early maturing, high-yielding fine-grain rice varieties with market acceptance. [ABSTRACT FROM AUTHOR]

This study was aimed to investigate combining ability and genetic parameters in summer squash (cucurbita pepo L.). Eight inbred lines of summer squash were crossed in line x tester method in summer season 2020. The parental lines (3 tester and 5 lines) and their off springs (15 hybrids) were planted out in the summer season 2021 at vegetable field, Horticulture Department, College of Agricultural Engineering Science, Duhok University. The experiment lay out using randomized complete block design with three replications. The results indicated that the mean square for genotypes were highly significant effect for tester, line and line x tester in all studied traits. The Tester LBL2 and line PEP1670 were the best combiner for days to 50% female flowering, number of fruit plant-1 and yield kg plant-1 . The crosses (LBL2 X N33133) and (LES3 X CNS2881) exhibited significant positive effect of specific combining ability for fruit length cm, number of fruit plant-1 and yield plant-1 . The heritability in broad sense were higher than narrow sense heritability for all studied traits ranged between 93% for days to 50% female flowering to 40% for fruit weight. The average degree of dominance less than one in all traits except days to 50% female flowering and fruit length. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Plant Production is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the current study, 20 elite rice genotypes were crossed with four CMS lines- CMS 23A, CMS 59A, CMS 64A and JMS 13A in a line x tester mating design and assessed alongside standard controls (JKRH 3333 and MTU 1001) to determine the best heterotic combinations in terms of grain yield and yield component characters at the Rice Research Centre, Rajendranagar. Eight restorer lines were found in Kharif 2018–19 based on pollen and spikelet fertility (MTU 1153, RNR 26015, RNR 28355, JGL 25960, MTU 1010, IET 27253, RNR 26085 and JAYA). The resulting 32 hybrids of 8 restorer lines and their corresponding CMS lines are studied for combing ability and heterosis. The degree of heterosis varied between traits. Three of the 32 hybrids under study had considerable standard heterosis for grain yield viz., JMS 13A x MTU 1153, CMS 59A x RNR 26015 and CMS 64A x MTU 1153, which outperformed the best checks JKRH 3333 and MTU 1001. The best experimental hybrid, JMS 13A x MTU 1153, yielded the most grain yield per plant, 62.89g (Table 1). Further testing of these three experimental hybrids will take place in areas conducive to extensive commercialization.

The study was carried out to learn about the nature of gene action and combining ability in rice hybrids for grain yield and its component traits. For this, eight lines were crossed with four testers in an L x T mating design. The analysis of variance revealed significant variance for all the characters studied among the parents and hybrids. GCA variances were higher than SCA variances for most of the characters, indicating the predominance of additive gene action, while SCA variances were higher than GCA variances for number of productive tillers per plant, pollen fertility, hulling, milling, head rice recovery and grain yield per plant, indicating the predominance of non-additive gene action. The testers JMS 13A (3.91) and CMS 59A (2.46), as well as the lines MTU 1153 (9.52), RNR 28355 (3.26) and RNR 26085 (3.09), were the best combiners for grain yield and important yield components due to positive GCA effects. Based on SCA effects and corresponding mean performance for grain yield and its component traits, the hybrids CMS 59Ax RNR 26015, CMS 23A x JGL 25960, CMS 64Ax RNR 26015 and JMS 13Ax MTU 1153 were identified as the best specific combiners. These hybrids could be tested in multi-environment trials for commercial use.

A study was carried out to assess the combining ability of ten CMS lines with four testers using the line x tester method. Biometrical observations were taken for days to 50% flowering, plant height, head diameter, days to maturity, volume weight, hundred seed weight, seed yield /plant, oil content and oil yield/plant. Specific combing ability variance was greater than the general combining ability variance for all the characters which indicated that non-additive gene action played a major role in inheritance. The gca of parents were not in agreement with the per se performance for various traits. Hence, the selection of parents should be based on gca alone for a breeding programme. Three lines viz., COSF 12A, COSF 13A and CMS 207A, and tester IR 6 were identified as good general combiners for seed and oil yield. Among the hybrids generated using good general combiners, COSF 13A x IR 6 had the additive type of gene action for seed and oil yield per plant. In general, most of the crosses had non-significant sca for oil yield per plant and oil content which indicated the presence of an additive type of gene action. Hence, the selection of good general combiners for oil content, seed and oil yield will help to evolve high oil yielding hybrids in sunflowers.

Abstract To generate high-yielding cultivars with favorable fiber quality traits, cotton breeders can use information about combining ability and gene activity within a population to locate elite parents and potential F1 crosses. To this end, in the current study, twelve cotton parents (eight genotypes as female parents and four testers) and their F1 crosses obtained utilizing the linex tester mating design were evaluated for their general and specialized combining abilities (GCA and SCA, respectively) of yield traits. The findings showed that for all the investigated variables, variances owing to genotypes, parents, crosses, and parent vs cross showed extremely significant (P ≤ 0.01) differences. Additionally, throughout the course of two growing seasons, the mean squares for genotypes (parents and crosses) showed strong significance for all the variables under study. The greatest and most desired means for all the examined qualities were in the parent G.94, Pima S6, and tester G.86. The best crossings for the qualities examined were G.86 (G.89 × G.86), G.93 × Suvin, and G.86 × Suvin. The parents' Suvin, G89x G86 and TNB were shown to have the most desired general combining ability effects for seed cotton yield/plant, lint yield/plant, boll weight, number of bolls/plants, and lint index, while Suvin, G.96 and pima S6 were preferred for favored lint percentage. For seed cotton yield, lint percentage, boll weight, and number of bolls per plant per year, the cross-G.86 x (G.89 × G.86) displayed highly significant specific combining ability impacts. The crosses G.86 × Suvin, Kar x TNB, G.93 × Suvin, and G.93 × TNB for all the studied traits for each year and their combined were found to have highly significant positive heterotic effects relative to better parent, and they could be used in future cotton breeding programs for improving the studied traits.

Water scarcity is a crucial environmental stress that constrains rice growth and production. Thus, breeding for developing high-yielding and drought-tolerant rice genotypes is decisive in sustaining rice production and ensuring global food security, particularly under stress conditions. To this end, this study was conducted to evaluate the effects of water deficit on 31 genotypes of rice (seven lines, viz., Puebla, Hispagran, IET1444, WAB1573, Giza177, Sakha101, and Sakha105, and three testers, viz., Sakha106, Sakha107, and Sakha108) and their 21 crosses produced by line × tester mating design under normal and water deficit conditions; this was to estimate the combining ability, heterosis, and gene action for some traits of physiological, biochemical, and yield components. This study was performed during the summer seasons of 2017 and 2018. The results showed that water deficit significantly decreased relative water content, total chlorophyll content, grain yield, and several yield attributes. However, osmolyte (proline) content and antioxidant enzyme activities (CAT and APX) were significantly increased compared with the control condition. Significant mean squares were recorded for the genotypes and their partitions under control and stress conditions, except for total chlorophyll under normal irrigation. Significant differences were also detected among the lines, testers, and line × tester for all the studied traits under both irrigation conditions. The value of the σ²GCA variance was less than the value of the σ²SCA variance for all the studied traits. In addition, the dominance genetic variance (σ²D) was greater than the additive genetic variance (σ²A) in controlling the inheritance of all the studied traits under both irrigation conditions; this reveals that the non-additive gene effects played a significant role in the genetic expression of the studied traits. The two parental genotypes (Puebla and Hispagran) were identified as good combiners for most physiological and biochemical traits, earliness, shortness, grain yield, and 1,000-grains weight traits. Additionally, the cross combinations Puebla × Sakha107, Hispagran × Sakha108, and Giza177 × Sakha107 were the most promising. These results demonstrated the substantial and desirable specific combining ability effects on all the studied traits, which suggested that it could be considered for use in rice hybrid breeding programs. [ABSTRACT FROM AUTHOR]

In the current study, 20 elite rice genotypes were crossed with four CMS lines-CMS 23A, CMS 59A, CMS 64A and JMS 13A in a line x tester mating design and assessed alongside standard controls (JKRH 3333 and MTU 1001) to determine the best heterotic combinations in terms of grain yield and yield component characters at the Rice Research Centre, Rajendranagar. Eight restorer lines were found in Kharif 2018-19 based on pollen and spikelet fertility (MTU 1153, RNR 26015, RNR 28355, JGL 25960, MTU 1010, IET 27253, RNR 26085 and JAYA). The resulting 32 hybrids of 8 restorer lines and their corresponding CMS lines are studied for combing ability and heterosis. The degree of heterosis varied between traits. Three of the 32 hybrids under study had considerable standard heterosis for grain yield viz., JMS 13A x MTU 1153, CMS 59A x RNR 26015 and CMS 64A x MTU 1153, which outperformed the best checks JKRH 3333 and MTU 1001. The best experimental hybrid, JMS 13A x MTU 1153, yielded the most grain yield per plant, 62.89g (Table 1). Further testing of these three experimental hybrids will take place in areas conducive to extensive commercialization. [ABSTRACT FROM AUTHOR]

Information on combining ability and standard heterosis are crucial for the success of any hybrid breeding program. The present study was conducted in sweet corn involving crossing of twenty inbreds as female lines and five inbreds as testers in line × tester mating fashion during kharif, 2019. Resulted 100 F1s were evaluated in rabi, 2019-2020 for twelve yields and its attributing traits. Analysis of variance for combining ability revealed the existence of wider variability in the material studied exhibiting significant differences due to lines, testers, hybrids and various interactions. Non-additive gene action was observed pre-dominant for all the traits. Inbreds SCGP-88, SCGP-111, SCGP-36-3- 1, SCGP-91, BSL-4, SCGP-44-2, VNR-SC-24, VNR-SC-23, SCGP-66-1 and SCGP-61-1-4 were identified as good general combiners. Crosses viz., SCGP-207-1 × SCGP-44-2, SCGP-54 × VNR-SC-29, SCGP-42 × SCGP-80, SCGP-82 × SCGP-80 and SCGP-66-1 × SCGP-44-2 were identified as promising hybrid combinations based on per se performance, sca effects and standard heterosis over the commercial checks.

The present study was conducted to estimate the combining ability and heterosis in pearl millet hybrids. Forty five pearl millet hybrids were developed using three male sterile lines (A line) with fifteen restore lines (R line) through the Line x Tester mating approach and were evaluated during kharif, 2018. Analysis of variance revealed that the mean square of treatments showed significance for all the traits. For days to 50 % flowering and days to maturity, lines viz., ICMA 93333, ICMA 97111, BIB 186, BIB 193 and BIB 281 had negative gca effect so these lines can be used as parents for hybrid development under harsh environmental conditions. Based on sca effect, heterosis and per se performance, crosses ICMA 97111 x BIB 208, ICMA 93333 x BIB 186 and ICMA 88004 x BIB 283 were identified as potential crosses for commercial exploitation of heterosis in pearl millet.

Water scarcity is a crucial environmental stress that constrains rice growth and production. Thus, breeding for developing high-yielding and drought-tolerant rice genotypes is decisive in sustaining rice production and ensuring global food security, particularly under stress conditions. To this end, this study was conducted to evaluate the effects of water deficit on 31 genotypes of rice (seven lines, viz., Puebla, Hispagran, IET1444, WAB1573, Giza177, Sakha101, and Sakha105, and three testers, viz., Sakha106, Sakha107, and Sakha108) and their 21 crosses produced by line × tester mating design under normal and water deficit conditions; this was to estimate the combining ability, heterosis, and gene action for some traits of physiological, biochemical, and yield components. This study was performed during the summer seasons of 2017 and 2018. The results showed that water deficit significantly decreased relative water content, total chlorophyll content, grain yield, and several yield attributes. However, osmolyte (proline) content and antioxidant enzyme activities (CAT and APX) were significantly increased compared with the control condition. Significant mean squares were recorded for the genotypes and their partitions under control and stress conditions, except for total chlorophyll under normal irrigation. Significant differences were also detected among the lines, testers, and line × tester for all the studied traits under both irrigation conditions. The value of the σ²GCA variance was less than the value of the σ²SCA variance for all the studied traits. In addition, the dominance genetic variance (σ2D) was greater than the additive genetic variance (σ2A) in controlling the inheritance of all the studied traits under both irrigation conditions; this reveals that the non-additive gene effects played a significant role in the genetic expression of the studied traits. The two parental genotypes (Puebla and Hispagran) were identified as good combiners for most physiological and biochemical traits, earliness, shortness, grain yield, and 1,000-grains weight traits. Additionally, the cross combinations Puebla × Sakha107, Hispagran × Sakha108, and Giza177 × Sakha107 were the most promising. These results demonstrated the substantial and desirable specific combining ability effects on all the studied traits, which suggested that it could be considered for use in rice hybrid breeding programs.

Genetic evaluation of segregating populations is one of the primary activities of cotton breeders. Seven cotton genotypes were crossed in a line × tester mating design. The population of 12 F1, 12 F2 and their parents were tested in Randomized Complete Block Design with three replications at the Nazilli Cotton Research Institute of Türkiye during the 2014/2015 cotton-growing season. The genetic variability was significant for all characters studied. s2GCA / s2SCA indicated non-additive gene action in controlling seed cotton yield (F2), ginning out-turn (F1) and fiber quality traits for both generations. The highly favourable GCA effects for seed cotton yield and fiber strength were recorded in the Carmen cultivar. Carmen × Carisma hybrid exhibited high mean performance and SCA effects for seed cotton yield and fiber strength, while the performance of Gloria × ST-468 was superior in terms of ginning out-turn. We concluded that individual plants with desired traits should be selected in later generations due to the preponderance of non-additive gene actions. [ABSTRACT FROM AUTHOR]

The study was carried out to learn about the nature of gene action and combining ability in rice hybrids for grain yield and its component traits. For this, eight lines were crossed with four testers in an L x T mating design. The analysis of variance revealed significant variance for all the characters studied among the parents and hybrids. GCA variances were higher than SCA variances for most of the characters, indicating the predominance of additive gene action, while SCA variances were higher than GCA variances for number of productive tillers per plant, pollen fertility, hulling, milling, head rice recovery and grain yield per plant, indicating the predominance of non-additive gene action. The testers JMS 13A (3.91) and CMS 59A (2.46), as well as the lines MTU 1153 (9.52), RNR 28355 (3.26) and RNR 26085 (3.09), were the best combiners for grain yield and important yield components due to positive GCA effects. Based on SCA effects and corresponding mean performance for grain yield and its component traits, the hybrids CMS 59Ax RNR 26015, CMS 23A x JGL 25960, CMS 64Ax RNR 26015 and JMS 13Ax MTU 1153 were identified as the best specific combiners. These hybrids could be tested in multi-environment trials for commercial use. [ABSTRACT FROM AUTHOR]

Cotton is considered as the main crop in the agricultural sector of Pakistan. Water deficiency in this region in recent years has reduced the chances of high yields of cotton. Selection and creation of high-yielding varieties of cotton, even in water deficit conditions, is one of urgent tasks of today. For this purpose, 40 diverse genotypes of upland cotton were screened in normal and water deficit conditions in triplicate arrangement under split plot in a randomized complete block design. All the genotypes showed significant difference under both water regimes. Ten upland cotton accessions were screened out as water deficit tolerant (VH-144, IUB-212, MNH-886, VH-295, IR-3701, AA-802, NIAB-111, NS-121, FH-113, and FH-142) and five as water deficit sensitive (IR-3, CIM-443, FH-1000, MNH-147, and S-12) based on seed cotton yield and stress susceptibility index. These tolerant and sensitive genotypes were crossed in line x tester mating design. For further evaluation of genetic material, the seed of 50 F1 crosses and their 15 parents were field planted under normal and water deficit conditions during next cotton growing season. Traits related to yield under the study showed significant variations among the accessions and their half sibs. The results of the principal component analysis (PCA) exhibited that total variation exhibited by factors 1 and factor 2 were 55.55 and 41.95%, respectively. PCA transformed the variables into three factors, and only two factors (F1 and F2) had eigenvalue>1. The degree of dominance revealed that all parameters were highly influenced by non-additive gene action under both water regimes. Furthermore, the line VH-295 and tester CIM-443 had better yield performance under water deficit stress. The cross-combinations, viz., VH-144 x S-12, NIAB-111 x IR-3, and VH-295 x MNH-147, were the best for yield contributing traits. These combinations may be helpful for germplasm enhancement on large scale under water scarcity. All the studied traits have non-additive types of gene action suggesting the usage of these genotypes in cotton hybrid development program against water deficit tolerance. [ABSTRACT FROM AUTHOR]

To generate high-yielding cultivars with favorable fiber quality traits, cotton breeders can use information about combining ability and gene activity within a population to locate elite parents and potential F1 crosses. To this end, in the current study, twelve cotton parents (eight genotypes as female parents and four testers) and their F1 crosses obtained utilizing the linex tester mating design were evaluated for their general and specialized combining abilities (GCA and SCA, respectively) of yield traits. The findings showed that for all the investigated variables, variances owing to genotypes, parents, crosses, and parent vs cross showed extremely significant (P ≤ 0.01) differences. Additionally, throughout the course of two growing seasons, the mean squares for genotypes (parents and crosses) showed strong significance for all the variables under study. The greatest and most desired means for all the examined qualities were in the parent G.94, Pima S6, and tester G.86. The best crossings for the qualities examined were G.86 (G.89 × G.86), G.93 × Suvin, and G.86 × Suvin. The parents' Suvin, G89x G86 and TNB were shown to have the most desired general combining ability effects for seed cotton yield/plant, lint yield/plant, boll weight, number of bolls/plants, and lint index, while Suvin, G.96 and pima S6 were preferred for favored lint percentage. For seed cotton yield, lint percentage, boll weight, and number of bolls per plant per year, the cross-G.86 x (G.89 × G.86) displayed highly significant specific combining ability impacts. The crosses G.86 × Suvin, Kar x TNB, G.93 × Suvin, and G.93 × TNB for all the studied traits for each year and their combined were found to have highly significant positive heterotic effects relative to better parent, and they could be used in future cotton breeding programs for improving the studied traits. [ABSTRACT FROM AUTHOR]

Experiments were conducted to study genetics and combining ability for yield and its attributes under Irrigated (E1) and Rainfed (E2) conditions using F1 hybrids derived from Line X Tester mating design by crossing eleven lines with three testers. Significant differences were observed among all the genotypes for all the traits in both E1 and E2 environments. The σ2gca/σ2sca ratio indicated the predominance of non-additive gene action for all the characters in both environments. Therefore, this component of the variance can be utilized in the breeding program through the exploitation of heterosis and the selection process for identification of superior plant types should be postponed to further generations like F4 or F5. Based on combining ability effect and per se performance in rainfed conditions, parents UP2572 and VL3001 were identified as good general combiners for grain yield per plant. In cross combinations, cross PRL/2*PASTOR//PBW343*2/KUKUNA/3/ROLF07/4/BERKUT//... × WH1142 and UP2572 × WH1142 were identified as the best specific combiners for grain yield per plant under irrigated and rainfed conditions, respectively. So, these identified parents and cross combinations can be exploited for developing water stress tolerant cultivars by identifying transgressive segregants in further breeding cycles. [ABSTRACT FROM AUTHOR]

To understand the effect of heat stress on morphology and physiology of the cotton, eight cotton genotypes with their 15F1 hybrids (five lines, three testers) were grown in the field conditions under randomized complete block design (RCBD) with two treatments i.e. normal and high-temperature stresses with two replications followed by split-plot arrangement. Data were collected for biochemical and yield-related parameters. Mean values of all studied traits were reduced significantly under high-temperature stress whilst the mean value of lint%, catalase activity, total soluble proteins, peroxidase, and carotenoids were increased under high-temperature. Under both conditions, the number of bolls, boll weight, seed cotton yield, lint index, seed mass per boll, hydrogen peroxide content, catalase activity, total soluble proteins, carotenoids, and chlorophyll contents had high heritability values along with high genetic advance percent mean which revealed, these traits were controlled by additive gene action. The lint%, seed index, short fiber index, fiber strength, fiber fineness, upper half mean length and peroxidase activity had high heritability with moderate genetic advance under heat stress conditions which showed, these traits were controlled by non-additive gene action. Under both temperature conditions, FH-458, IUB-65, CRS-2, and FH-313 were good general combiners for physicochemical and yield-related traits. The cross combination of IUB-013× CRS-2 and FH-458× FH-313 were good specific combiner for plant height and seed cotton yield whilst for fiber quality and biochemical traits, the best specific combiners were VH-329× FH-313 and IUB-013× CRS-2. These identified parents and cross combinations might be used for improving already present commercial varieties under high-temperature stress.

An investigation was undertaken with 54 hybrids obtained by crossing nine lines and six testers in L x T mating design to analyse heterosis and combining ability. Sixteen biometric traits were measured. The SCA variance was observed to be more than GCA variance for all the traits except for days to 50% flowering and days to green fodder harvest indicating the preponderance of non-additive gene action governing the traits studied. Results of gca effects and the mean performance of parents revealed that the genotypes viz., IP 17424, IP 17435, CO 8, GP 15074 and PT 5588 were identified as good combiners for green fodder yield and its component traits. Based on the standard heterosis over the standard check TNAU pearl millet hybrid CO 9, the hybrids viz., PT 5701 x GP 18219, CO 8 x PT 5588, CO 8 x GP 16026, IP 17424 x GP 15074, IP 17424 x PT 5682, IP 17424 x PT5365, IP 17424 x PT 5588 and IP 17424 x GP 18219 recorded superior heterosis for green fodder yield. Considering sca effects, mean performance and standard heterosis, the hybrids viz., IP 17424 x GP 15074, IP 17424 x PT 5682 and CO 8 x PT 5588 were identified as the superior performing hybrids for green fodder yield. Similarly, for high crude protein, the hybrid PT 5652 x PT 5588 was identified as the superior one. The above hybrids could be exploited further to improve green fodder yield with quality traits in pearl millet.

A determinate type hybrid of tomato ‘NIAB JAUHAR’ earlier denominated as NBH-25 was developed by crossing a local genotype ‘NB-13’ with an exotic inbred line ‘NB-6’ (a derivative of line LBR-10 provided by World Vegetable Centre, Taiwan). The genetic purity of the F1 hybrid, NIAB JAUHAR was confirmed using DNA-PCR based SCAR marker. NIAB JAUHAR showed 41% advantage in yield in preliminary while 18-34% in multi-location yield trials over commercial check hybrid T-1359 during 2012-16. Disease severity index recorded in two consecutive years scaled NIAB JAUHAR as moderately resistant to early and late blight diseases. Reaction to fruit borer infestation on NIAB JAUHAR was less than economic threshold level. NIAB JAUHAR possesses high fruit weight, fruit firmness, vitamin A and C, lycopene and low contents of sugar against standard. It gives a high range of productivity 56-61 t. ha-1 when transplanted around mid of November with NPK application of 225:90:125 kg. ha-1 . Due to its superior characteristics, Punjab Seed Council Lahore approved this hybrid for commercial cultivation in 2018. Seed production of NIAB JAUHAR can be started on commercial scale in order to supply quality seed at low price to the growers and to save foreign exchange incurred on import of tomato seed every year in Pakistan [ABSTRACT FROM AUTHOR]

Information on combining ability and standard heterosis are crucial for the success of any hybrid breeding program. The present study was conducted in sweet corn involving crossing of twenty inbreds as female lines and five inbreds as testers in line × tester mating fashion during kharif, 2019. Resulted 100 F1 s were evaluated in rabi, 2019-2020 for twelve yields and its attributing traits. Analysis of variance for combining ability revealed the existence of wider variability in the material studied exhibiting significant differences due to lines, testers, hybrids and various interactions. Non-additive gene action was observed pre-dominant for all the traits. Inbreds SCGP-88, SCGP-111, SCGP-36-3- 1, SCGP-91, BSL-4, SCGP-44-2, VNR-SC-24, VNR-SC-23, SCGP-66-1 and SCGP-61-1-4 were identified as good general combiners. Crosses viz., SCGP-207-1 × SCGP-44-2, SCGP-54 × VNR-SC-29, SCGP-42 × SCGP-80, SCGP-82 × SCGP-80 and SCGP-66-1 × SCGP-44-2 were identified as promising hybrid combinations based on per se performance, sca effects and standard heterosis over the commercial checks. [ABSTRACT FROM AUTHOR]

Heat tolerance is a physiologically and genetically complex trait regulated by multiple genes. To investigate the genetic basis of heat tolerance, eight parents (five lines and three testers) and their fifteen F1 hybrids were evaluated under normal and high-temperature stress conditions for two consecutive years. Data were recorded for plant height, number of bolls, boll weight, seed cotton yield, ginning out turn (GOT%), H2O2, catalase, peroxidase, super-oxidase dismutase, total soluble proteins, carotenoids, chlorophyll a & b contents, short fiber index, fiber strength, UHML, micronaire value, reflectance, and uniformity index. Line × tester analysis suggested that the contribution of lines was higher than testers. Non-additive gene action was observed for all studied traits. The variances of SCA were greater than GCA variances for all studied traits revealed that these traits were governed by a few largely dominant genes. Fb-Shaheen, Eagle-2 and JSQ White Gold were found good general combiner whereas the cross Fb-Shaheen × JSQ White Gold was a good specific combiner and revealed significant better parent heterosis for most of the traits during two years under normal and high temperature stress conditions. The information obtained could be utilized in a breeding program for the development of new synthetic varieties of heat tolerance. [ABSTRACT FROM AUTHOR]

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Twelve parental genotypes and twenty F1 hybrids developed in a Line x Tester fashion were used in the present study to estimate gene action, combining ability and standard heterosis for eleven quantitative and five quality traits in cotton. All the traits studied exhibited greater SCA variance than GCA except days to fifty per cent flowering suggesting that these traits are controlled by dominant gene action. Among the parents used, SVPR 2 and TSH 325 were detected with higher general combining ability for seed cotton yield and should be given importance while developing hybrids or recombinants. The hybrids namely SVPR 2 x TSH 325, SVPR 2 x Suraj and GJHV 370 x PBH 116 were identified as the best hybrids for seed cotton yield and SVPR 2 x TCH 1828 for fibre properties and recommended for heterosis breeding. Besides, the hybrid between GJHV 370 x CPD 1702 was suggested for recombination breeding for earliness and ginning percentage as it fulfilled the criteria of non-significant sca effects for hybrid and significant gca effects for respective parents.

The 21 hybrids were generated by applying LxT mating design using seven lines and three testers and were subjected to study combining ability for nine yield traits of barley. ANOVA was significant for GCA and SCA effect, indicating parents and crosses differed significantly with regard to general and specific combining ability, respectively. The GCA effect recorded for most of the traits were low and non-significant. However, two lines EC-667509 and EC-667365; one tester, NDB3 recorded the high GCA effect in three traits eachviz., productive tillers per plant, the number of grains per spike and 1000-grain weight; grain yield per plant, harvest index and 1000-grain weight; days to 75% maturity, the number of grains per spike and harvest index, respectively. Non-significant SCA effect for all the traits was observed in 12 out of 21 crosses. In respect to the SCA effect, cross EC-667498 x Azad performed better than the remaining cross combinations, as it recorded the high SCA effect in desirable direction in five out of nine traits.

The present investigation was made to study the combining ability and gene action in sunflower. Five standard CMS lines and nine restorers were included as parental material. Forty five hybrids were developed andevaluated in RBD at Oilseeds Research Station, Latur during Rabi season 2018-2019 for 9 characters viz., days to 50 percent flowering, days to maturity, plant height, head diameter, seed yield per plant, seed filling percentage, 100 seed weight, volume weight and oil content.CMS 10A was good general combiner for days to 50% flowering, days to maturity, head diameter, 100 seed weight, seed yield per plant, volume weight and seed filling percentage. Similarly CMS 519A and CMS 62A were found to be good general combiners for seed yield and component traits. Among the testers, TSG-04 was good general combiner for days to 50% flowering, days to maturity, plant height and 100 seed weight. Similarly, TSG-281 and SCG-04 exhibited good general combining ability for oil content and component traits. Out of 45 hybrids, five hybrids viz. CMS 62A X SCG-04, CMS 234-1017A X TSG-327, CMS 234-1017A X TSG-111, CMS SUN-35-519A X TSG-289 and CMS 519A X TSG-289 exhibited the significant desirable sca effect for seed yield and component traits. The variance component due to specific combining ability was greater in magnitude than that of general combining ability for all the characters except seed yield per plant, volume weight and seed filling which indicated that the non-additive gene action played important role for the inheritance of these traits whereas seed yield per plant, volume weight and seed filling were governed by additive gene action.

Line x tester analysis was carried out involving six lines and 4 testers for seed cotton yield, yield contributing traits and fibre quality traits for estimation of combining ability effects of parents for sixteen characters. The analysis of combining ability revealed that the variance for SCA were larger than GCA except uniformity ratio which corresponds with non- additive gene action which can be improved by heterosis breeding. Based on the high per se performance and high gca effect, the parents C 10-8 and RAHC 1917 were considered as best general combiner for boll weight and single plant yield per plant. Regarding boll weight, TCH 1822 and C 10-8 were good general combiners with significantly high per se performance. These parents were found to be recorded as good general combiners for different characters. Hence, these can be used in recombination breeding to obtain more favorable gene recombinations for seed cotton yield. The cross TCH 1819 x RS 2821 showed a positive and significant sca effect for the number of bolls, boll weight and seed cotton yield. The cross Anjali x CPD 1501 showed a positive and significant sca effect for boll weight, lint index, seed index and seed cotton yield. The cross TCH 1926 x RS 2821 exhibited a positive significant sca for the number of bolls, 2.5 % span length and fibre strength. The non – additive gene action has played an important role in expression of seed cotton yield and its component traits which justify the heterosis breeding and its exploitation commercially.

The proficiency and efficacy of the parental selection programmes in most of the crops including popcorn can be significantly improved by estimating the combining ability and its effects. The present study was planned with an aim to assess the combining ability variances and effects in 28 cross combinations developed by crossing eight inbred lines of popcorn in half diallel fashion design (without reciprocals). The thirty eight genotypes including twenty eight hybrids along with their eight parents and two checks were evaluated in randomized complete block design to estimate the GCA and SCA of parents as well as crosses. Results for combining ability shown that mean sum of squares due to hybrids and parents vs. hybrids were significant, which in turn exhibits significant genotypic differences for all the characters under study except grain protein content. It was also apparent that both general combining ability and specific combining ability variances were significant for all the characters except grain protein content which indicated importance of both additive and non additive gene action in the inheritance of these traits. The inbred lines viz., HKI PC 1473-5, HKI PCBT 3, HKI PC 4B were found as good combiners and desirable for both grain yield and quality traits with high popping expansion. The cross combination HKI PC 1473-5 x HKI PCBT 3, HKI PC 4 x HKI PC 7 and HKI PC 4B x HKI PCBT 3 showed good SCA effects for grain yield, yield related traits and quality traits and thus indicated non additive gene effects is more pronounced and selection may prove reliable in maize hybridization programme for improvement of yield and other characters.

To understand the effect of heat stress on morphology and physiology of the cotton, eight cotton genotypes with their 15F1 hybrids (five lines, three testers) were grown in the field conditions under randomized complete block design (RCBD) with two treatments i.e. normal and high-temperature stresses with two replications followed by split-plot arrangement. Data were collected for biochemical and yield-related parameters. Mean values of all studied traits were reduced significantly under high-temperature stress whilst the mean value of lint%, catalase activity, total soluble proteins, peroxidase, and carotenoids were increased under high-temperature. Under both conditions, the number of bolls, boll weight, seed cotton yield, lint index, seed mass per boll, hydrogen peroxide content, catalase activity, total soluble proteins, carotenoids, and chlorophyll contents had high heritability values along with high genetic advance percent mean which revealed, these traits were controlled by additive gene action. The lint%, seed index, short fiber index, fiber strength, fiber fineness, upper half mean length and peroxidase activity had high heritability with moderate genetic advance under heat stress conditions which showed, these traits were controlled by non-additive gene action. Under both temperature conditions, FH-458, IUB-65, CRS-2, and FH-313 were good general combiners for physicochemical and yield-related traits. The cross combination of IUB-013× CRS-2 and FH-458× FH-313 were good specific combiner for plant height and seed cotton yield whilst for fiber quality and biochemical traits, the best specific combiners were VH-329× FH-313 and IUB-013× CRS-2. These identified parents and cross combinations might be used for improving already present commercial varieties under high-temperature stress. [ABSTRACT FROM AUTHOR]

Six lines and four testers were involved in the combining ability and gene action study in line x tester mating design to discern desirable general and specific combiner for breeding programme. The combining ability variance indicated that sca variance was higher than gca variance indicating the preponderance of non-additive gene action for the characters studied viz., days to 50 percent flowering, panicle length, plant height, the number of grains per panicle, the number of tillers per plant, the number of productive tillers per plant, flag leaf length, flag leaf breadth, spikelet fertility, test weight and single plant yield. Among the parents, Improved White Ponni, RG192, RG163 and RG105 were discovered as the best general combiners for single plant yield. The cross combinations viz., ADT37 X RG163, ADT43 X RG105, ADT45 X RG163, ADT(R)48 X RG105, CO51 X Kavuni and Improved White Ponni X RG192 were the ideal specific combiners for single plant yield. Therefore, the aforementioned cross combinations may be employed in the upcoming breeding programmes in order to develop a higher heterosis for yield.

Seven cucumber (Cucumissativus L.) genotypes (3 lines and 4 testers) were crossed in a line × tester mating design. The resultant 12 hybrids and their parents were evaluated using Randomised Block Design with two replications during Kharif 2018. Sufficient genetic variability was observed for all the characters under study. In this study, the parents L2 (Koradacherry local), T2 (Orathanadu local) and T3 (Aipatti local) exhibited high positive GCA (General Combining Ability) effects for yield related traits and high negative GCA effects for earliness characters. The parent T2 identified in this study may be used in multiple crossing programme to isolate high yielding varieties. Among the hybrid combinations, L2xT3, L1xT2 and L3xT4 expressed the maximum positive significant SCA (Specific Combining Ability) effects for yield and yield associated characters. In the above cross combinations one parent was a good combiner and the other was an average/poor combiner; hence the hybrids can be exploited for transgressive selection.

The general and specific combining ability effects and variances for eight characters related to seed yield and its contributing traits in safflower were studied using Line x Tester mating design in forty CMS based hybrids, involving 20 lines (males) and two testers (females) along with three checks (PKV PINK, AKS 207 and PBNS 12). Combining Ability Analysis indicated the predominance of non-additive gene action for all the traits under study. Out of 20 males, GMU 3876, GMU 3924, GMU 3965 and AKS CMS 2B were identified as good general combiners for seed yield per plant, whereas, S-518, CCC-B2 and AKS 325 were identified as good general combiners for other yield contributing traits, and the parents GMU 3876, GILA and AKS CMS 2B for oil content. Hence, these parents may be exploited in further breeding programme to improve the concerned traits. Three crosses viz., AKS CMS 2A X GMU 3876, AKS CMS 2A X GMU 3863 and AKS CMS 3A X AKS/NS1 were identified as promising crosses on the basis of SCA effects for seed yield per plant, with good GCA effect of one of the parents. Thus, these crosses may be used for further evaluation in preliminary or multi-location hybrid trials for the further exploitation at commercial level. The crosses viz., AKS CMS 2A X GMU 3965, AKS CMS 2A X GMU 3325 and AKS CMS 2A X AKS 325 performed well over the best check i.e. PKV PINK along with a positive and highly significant GCA effects of one of the parents involved in the cross and low SCA effects (non-significant), it is recommended to utilize these crosses further by generation advancement for the development of varieties after re-crossing with ‘B’ line of the respective CMS line.

An attempt was made to study the general and specific combining ability in sesame (Sesamum indicum L.) through line x tester analysis by using five lines and ten testers. A total of fifty crosses were developed and eleven quantitative traits were studied. Among the line AT-231 was the best general combiner for days to 50 % flowering, days to maturity, number of capsule per plant, number of seed per capsule, 1000 seed weight, oil content and seed yield per plant and the line RT-54 for days to maturity, width of capsule, 1000 seed weight and seed yield per plant and oil content. Among the tester KMR-69 showed positive gca effects for seed yield per plant and 1000 seed weight. The tester GT-3 was the best general combiner for days to 50 % flowering, oil content, length of capsule and width of capsule. The tester LOCAL was the best general combiner for number of capsule per plant, number of seed per capsule and 1000 seed weight. The tester PRACHI was the best general combiner for number of branches per plant. The cross RT-54 x KMR-69 exhibited significantly high sca effects for the characters viz., number of capsule per plant, width of capsule, 1000 seed weight and seed yield per plant and hence these crosses could be utilized for yield improvement through heterosis and pedigree breeding.