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Copyright of Canadian Journal of Plant Science is the property of Canadian Science Publishing 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.)

This study aimed to evaluate hybrids obtained by the cross among temperate × tropical elite maize lines, and to determine the genetic diversity and population differentiation of these inbred lines. Forty-nine hybrids were evaluated for seed yield, plant and ear heights, and for severity of Phaeosphaeria maydis and Exserohilum turcicum in four environments in Brazil. Hybrids were obtained from a partial diallel that involved seven tropical and seven temperate lines. Twenty-two SSR primers were used to evaluate the genetic relationship among the lines. Diallel showed the existence of significance for GCA and SCA effects; the genetic control of the traits was associated with additive and nonadditive genetic effect. Results showed that exotic and previously protected temperate maize germplasm may provide novel alleles for resistance to P. maydis and E. turcicum and increase yield in tropical maize. Tropical inbred lines were allocated in different heterotic groups, suggesting an admixture condition among temperate and tropical materials. [ABSTRACT FROM AUTHOR]

Production of high sunflower yield is important in sunflower breeding programs. With regards to the importance of estimation of general combining ability (GCA) and specific combining ability (SCA), genetic evaluation of sunflower seed yield was carried out in normal and water stress conditions using biplot analysis of 6×6 diallel design. Parental lines and their progenies were investigated using a randomized complete block design with three replications in each condition in greenhouse. According to the separate analysis of variance, mean squares of genotypes were significant for seed yield in 0.01 probability level in both conditions. The first two principal components explained 77.9% and 82.5% of the variation for seed yield in normal and stress conditions respectively. Therefore, it is possible to extract any information by using graphical method of biplot. Among studied parental lines, LR25 had the positive and the highest general combining ability in both states. RHA266 had positive and the highest specific combining ability in water stress condition and genotype LR4 had the negative and the highest specific combing ability in normal condition. Considering the polygon graphs of biplot, cross LR25 × LR4 in normal condition and crosses including LR25 × C104, LR55 × RHA266 and C100 × RHA266 in water stress condition, depicted high level of heterosis for sunflower yield. Results revealed that genotype C104 is suitable tester for recognition of general combining ability of studied genotypes.

This study was performed to investigate combining ability effects and gene actions for some important traits using diallel mating design in wheat at Peshawar Pakistan. Eight wheat genotypes viz. Janbaz (JNB), Fakhr-i-Sarhad (FS), Pirsabak 2005 (PS), AUP-5008 (AUP), Saleem 2000 (S2K), Tatara (TTR), Barsat (BST) and Siren (SRN) were crossed in all possible combinations during 2011-12 cropping season. The resultant F1 hybrids were planted following a randomized complete block design using three replications in the subsequent wheat growing season of 2012-13. For days to maturity, F1 cross combination PS × FS among the F1 hybrids showed earliness (160.7) whereas F1 cross combination BST × SRN and JNB × BST ranked first among the crosses for spike length (15.9 cm). Among the F1 hybrids, FS × SRN and TTR × BST displayed maximum spikelets spike-1 (24.3) whereas for F1 cross combinations, FS × SRN and TTR × BST had the highest number of grains spike-1 (58.9). The results of inheritance studies discovered that both additive and dominance type of inheritance mechanism was involved in the expression for maturity trait, plant stature, spike length, spikelet spike-1 and grains spike-1. Negative intercept of regression line indicated the major role of over-dominance in the inheritance of plant height, spikelets spike-1while for grains spike-1 the positive intercept of regression line indicated predominance of partial dominance in inheritance.F1 cross combination FS × JNB were observed as good specific combiners for spike length, while hybrids FS × SRN and BST × S2K were revealed as good specific combiners for spikelets spike-1 and grains spike-1, respectively. These F1 cross combinations being good specific combiners for specific traits could be utilized in future breeding programs for the improvement of desired traits. [ABSTRACT FROM AUTHOR]

Introduction of clones from genetic groups that are underrepresented in the pedigree of commercial cacao varieties in West Africa represents an important aspect of cacao improvement strategy of broadening the genetic base to overcome current yield stagnation of the crop. The objective of the present study was to determine the combining abilities of more recently introduced cacao clones for yield and cropping efficiency in the early bearing years. Seven recently introduced clones were crossed as males to five clones commonly used in the seed gardens in Ghana using a North Carolina II design. The 35 F1 varieties and one commercial variety were evaluated in the field from June 2010 to March 2015 for four traits: increase in trunk cross-sectional area in the juvenile, and in the pod-bearing phases, bean yield and cropping efficiency. Though both GCA and SCA variances were significant for all traits, the ratios of GCA:SCA were much smaller than unity, indicating the importance of non-additive effects in the control of the traits. Among the set of clones therefore, prediction of F1 variety performance cannot be based on the GCA or per se (average) performance of the clones. Six varieties were more precocious, and eight had higher cropping efficiencies than the standard variety. Bean yields ranged from 0.74 to 1.05 t/ha/year in the fourth and fifth years after planting among the top six varieties. The study provides evidence of the large potential for productivity increase through the use of cacao clones beyond Pound's early introductions into West Africa. [ABSTRACT FROM AUTHOR]

A simple method of construction of mutually orthogonal Latin square of order p = 2m + 1 is proposed. Incomplete block designs for a complete diallel cross experiment known as method (4) of Griffing (1956) are derived using proposed mutually orthogonal Latin square. Optimality of these designs is considered when, in addition to the block effects and general combining abilities, the model also includes specific combining abilities. It is found that these designs remain optimal even in the presence of specific combining abilities. The analysis includes the analysis of variance and the estimation of general combining ability and of specific combining ability. The analysis is illustrated numerically. [ABSTRACT FROM AUTHOR]

In South Africa, Eucalyptus grandis is an important species due to its fast growth and general suitability of its timber for a range of products. However, E. grandis is susceptible to fungal diseases such as Crysoporthe austroafricana and Coniothyrium sp. cankers in the subtropical region of Zululand and is therefore mainly planted as a parental species in a hybrid combination with E. urophylla in this region. The current strategy is to maintain large breeding populations of both parental species in order to provide improved elite selections for hybrid crosses. In order to develop the best interspecific hybrid breeding strategy for E. grandis, it is important to first determine estimates of genetic parameters of the pure species parents. Estimating the genotype by environment interaction (GxE) is also necessary in proposing the basis for setting up breeding populations and selecting environmentally stable genotypes. With this in mind, two E. grandis full-sib progeny trials were planted in Zululand and one in the KwaZulu-Natal Midlands region. The aims of this study were firstly to determine the magnitude of GxE of E. grandis across the three sites; secondly, to estimate the genetic parameters for growth of the E. grandis parents selected for intraspecific crosses; and lastly, to identify the best parents to use for intra- and interspecific crosses in future hybrid breeding programmes. Results of our study indicated that GxE would be practically negligible for growth in Zululand and one group of elite parents can be used for hybrid crosses in this region. In general, growth traits were under low to moderate genetic control, and the variation in additive genetics enabled us to identify E. grandis parents that could be utilised for intraspecific crosses and deliver progeny with genetic gains of 28.4%. Our study also highlighted that a relatively large portion of the genetic variation was explained by dominance genetic variation and a strategy to capture this non-additive variation needs investigation. Although our study achieved the stated aims, it must be kept in mind that E. grandis is mainly used as a hybrid parent with E. urophylla in Zululand. A study to investigate whether the parents with good general combining ability values from our study are also good general combiners in interspecific hybrid combinations with E. urophylla needs to be conducted. [ABSTRACT FROM AUTHOR]

The study was conducted to estimate general combining ability (GCA) and specific combining ability (SCA) of 13 maize cultivars on grain yield and component traits using North Carolina mating design II (NCII). Genotype x environment interaction for the agronomic traits was also estimated. Crossing was carried out among thirteen elite maize cultivars which were planted in November 2014 under irrigation. The progenies were evaluated in April, 2015 during the early season and in August 2015, for the late season. Data were subjected to analysis of variance (ANOVA) and thereafter, GCA and SCA were estimated. The results showed that there was little variation among parental genotypes in the early season while in late season, the parents exhibited wider variations in yield component traits evaluated. GCA/SCA ratio showed preponderance of specific combining ability (SCA) effects for all the yield component traits studied in the early and late cropping seasons except for number of grain rows/ear and number of grains/row. This implies that SCA was more important in these maize cultivars as parents to hybrid or synthetic variety populations. Highly significant differences were observed for genotypes x season interaction in almost all the characters, indicating that selection should be carried out on seasonal basis. Five top performing hybrid genotypes were identified and selected based on grain yield from each of the seasons: (11A11990)*(11A11917); (11A11990)*(07A04207); (11A11990)*(11A11991); (11A11936)*(11011896) and (09A2567)*(11A11895) for the early season and (11A11990)*(11A11991); (11A11936)*(11A11991); (12C24114)*(11011896); (11A11990)*(11011896) and (11A11936)*(12C24117) for the late season. These genotypes are therefore recommended for use in population improvement programme. [ABSTRACT FROM AUTHOR]

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China 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.)

The purpose of this research was to evaluate the combining ability of six local Iranian and one imported cantaloupe cultivar. Heritability of traits was estimated using a half-diallel mating design. Seven parents and their crosses were evaluated in 2013 and 2014. The greatest general combining ability ( GCA) for yield and fruit number was for 'Rish-baba' (0.53 kg/plant and 0.3, respectively). The cultivar 'Ananasi' had the highest GCA for fruit weight and soluble solids content ( SSC) (0.088 kg and 1.4, respectively). 'Ananasi' presented the highest GCA values for fruit firmness, chlorophyll a and b and carotenoid content, as well as the highest total chlorophyll content. The cross Garmak × Rish-baba showed the highest specific combining ability ( SCA) for yield with heterosis value of 99%. High heritability estimates for SSC (0.52), flesh thickness (0.61) and concentration of chlorophyll a (0.7) were obtained. Although there were significant SCAs for yield, the parents are suggested to be improved prior to hybrid development. The parent 'Ananasi' appears to be a suitable donor in breeding programmes. [ABSTRACT FROM AUTHOR]

The general (GCA) and specific (SCA) combining abilities among eight cytoplasmic male sterile lines and six restorers as testers were estimated using line × tester method to assess the potential of the materials in the sunflower (Helianthus annuus L.) breeding program. Test cross progenies along with their parents were evaluated in two sowing dates. Both lines and testers had significant differences for all the traits except seeds per head. The lines: LA2 and LA7 were superior combiners with significant positive general combining ability (GCA) effects for seed yield and most of the yield components. Among the testers: RF1 and RF6 were good combiners for seed yield. Most of the lines and testers with significant positive GCA effects for seed yield had significant positive GCA effect for oil yield. LA7 × RF6 had significant positive specific combining ability (SCA) effects for seed width, seed yield and oil yield. The crosses LA4 × RF1 and LA7 × RF6 had significant SCA effects for seed yield and oil yield. Estimating degree of dominance more than one for all the traits except seeds per head and percentage of kernel indicate the importance of non additive genetic effects for them; therefore for improving these traits, hybrid breeding will be more effective. [ABSTRACT FROM AUTHOR]

Field experiments were conducted at National Horticultural Research Institute, Bagauda (11°33'N; 8°23'E) in the Sudan Savannah and Institute for Agricultural Research, Samaru (11011'N; 07038'E) in the Northern Guinea Savanna ecological zones of Nigeria. The experiments were conducted between July-October, 2014 rainy season to estimates mean squares for general combining ability (GCA), specific combining ability( SCA) and interaction between general combining ability and location (GCA x location) and specific combining ability and location Interactions ( SCA x location) for agronomic traits and kernel quality traits. The study comprised of 15 hybrid lines, 6 parental lines along with 4 checks which were laid out in partially balanced lattice design with three replications. Analysis of variance revealed significant (P≤ 0.01) GCA for days to maturity (27.74), ear length (8.85cm), ear diameter (22.25cm), plant height (1501.60cm), field weight (1.70kg), moisture content at harvest (16.48%) and yield (10947553.16 kgha-1) indicating the additive gene action contributing the expression of these traits. The mean squares due to SCA were highly significant (P≤ 0.01) for days to maturity (7.49), ear length (10.06cm), ear diameter (26.96cm) and moisture content at harvest (6.78%) indicating the preponderance of non-additive gene action in the expression of these traits. The mean squares for GCA× location and SCA× location were not significant for all traits except percent whole kernel which shows highly significant GCA × location interaction (2077.97%) and this indicated that, different parental genotypes behaved differently with respect to this trait under different location. [ABSTRACT FROM AUTHOR]

Knowledge of the general combining ability, ie the additive genetic component passed on by a parent to all his offspring, has a very high practical relevance in corn breeding programs. The objective of the research was to evaluate the additive genetic effects (general combining ability). The overall ability to combine inbred lines is particularly important in making valuable hybrids. By crossing known inbred lines with a high overall combining capability (for production or for another character) in a dialel system, it is normal to carry out a hierarchy of the respective inbred lines. [ABSTRACT FROM AUTHOR]

[Objectives] The paper was to screen resistant sugarcane varieties against brown stripe disease, and to breed disease-resistant germplasm resource. [Methods] The combining ability for resistance to sugarcane brown stripe disease was analyzed based on 23 female parents, 21 male parents and 29 cross combinations. [Results] The average herilabilily of resistance to sugarcane brown stripe disease successively were female parents (95.3%), cross combinations (93.0%) and male parents (79.1%). The general combining ability of 12 female parents showed negative effect, including Pma 98-40, Yacheng93-26, Yunrui 05-283, Yu-etang91-976, Chuanzhe 19, ROCIO, Yunzhe 06-80, ROC26, Zhanzhe 74-141, K86-110, Yunzhe 03-194 and ROC25. The general combining ability of 10 male parents showed negative effect, including Q 199, Yunrui 06-649, Yunrui 05-733, CP 84-1198, CP 88-1762, Yacheng 84-125, Yunrui 05-784, Yuetang 00-236, CP 72-3591 and CP 94-110. The special combining ability of 16 cross combinations showed negative effect, including Pma 98-40 × Yunrui 05-649, Yacheng 93-26 × Yunrui 05-733, Yunrui 05-283 × Q199, Yuetang 91-976 × CP 84-1198, Chuanzhe 19 × CP 88-1762 and ROCIO × Yuenong 73-204. [Conclusions] There were significant differences in combining ability among female parents, male parents and cross combinations, which were mainly controlled by additive and non-additive gene. [ABSTRACT FROM AUTHOR]

Heterosis and combining ability analysis of 10 x 10 diallel (excluding reciprocal) set of crosses in forage sorghum were done for yield and its contributing characters during the season of Kharif 2012 by raising the crop at Crop Research Center. All the 45 F1 hybrids and their ten parents were grown and selfed during Kharif season of 2013 for producing F2 seeds. All the 45 F1 hybrids and 45 F2 populations along with ten parents were sown in Randomized Block Design with three replication at Crop Research Center of Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut during the Kharif season of 2013. Observation were recorded on days to 50% flowering, plant height, leaf breadth, leaf length, leaves per plant, leaf area, leaf stem ratio, stem girth, total soluble solids, protein content and green fodder yield. ANOVA for combining ability revealed that the parent SSG 59-3 exhibited high general combining ability effect for all the characters except days to 50% flowering, leaf breadth, leaf stem ratio, stem girth, total soluble solids and protein content in both F1 and F2 generations. Promising parents viz., HC 171, UP chari 2, Pant chari 5 and Pant chari 6 which were having high general combining ability effects in desirable direction for green fodder yield and yield components character like plant height, leaf breadth, leaf length and stem girth may be incorporated in crossing programme to have better genotypes for better green fodder yield. The cross combinations namely, UP chari 2 x HC 171, Pant chari 5 x RSSV 9, Pant chari 5 x SSG 59-3, SSG 59-3 x Pusa chari 23, CSV 15 x Pant chari 6, G 48 x HC 171, CPVI 1724 x HC 171 and Pant chari 5 x G 48, which exhibited good specific combining ability effects for green fodder yield and its contributing traits such as days to 50% flowering, leaf breadth, leaf length, leaves per plant, leaf stem ratio and stem girth in both F1 and F2 generations. Nine cross combinations which revealed highest value of heterosis for leaves per plant and green fodder yield viz., SSG 59-3 x CSV 15, Pant chari 5 x CSV 15, RSSV 9 x HC 171, CSV 15 x UP chari 2, G 48 x UP chari 2, Pant chari 5 x HC 171, G 48 x HC 171, Pant chari 6 x CPVI 1724 and SSG 59-3 x Pusa chari 23 over better parent as well as economic parent may be exploited for developing hybrids for better yield in forage sorghum. [ABSTRACT FROM AUTHOR]

Six advance wheat lines namely B4N11, B6N5, B6N12, BRF1, BRF3 and BRF17 and four wheat cultivars namely Zam-04 (ZM04), Kohat-10 (KT10), Pirsabak-08 (PS08) and Janbaz (JZ) were crossed in line × tester mating to develop 24 F1 hybrids. The resultant hybrids along with parents were evaluated during cropping season 2012-13 at Cereal Crops Research Institute (CCRI), Pirsabak, Nowshera, Pakistan under rainfed environment, using RCB design with 3 replications. General combining ability (GCA), specific combining ability (SCA) and narrow sense heritability for maturity and yield components traits were determined. The main objective of the research was identification and proper selection of best performing wheat parental genotypes and best F1 crosses, based on GCA and SCA estimates. Significant differences were observed among the wheat genotypes for all the studied traits. The estimates of σ2gca and σ2sca and its ratio (σ2gca/σ2sca) indicated that non-additive genetic expression were pre-dominant for most of traits studied. Line BRF3 and testers ZM04 were good general combiners for most of traits under consideration, while F1 hybrids B4N11 × PS08, B4N11 × JZ, BRF1 × ZM04, BRF1 × KT10 were best specific combiners observed for several important traits including grain yield plant-1 which can be subsequently utilized in future wheat breeding to develop high yielding new wheat cultivars from transgressive segregants recovered in latter generations. [ABSTRACT FROM AUTHOR]

This study evaluated the genetic potential of parents used in sugarcane genetic breeding programs based on the performance of previously conducted single crosses. The average selection rate of each family, predicted using Best Linear Unbiased Prediction (BLUP) procedure, was used as a surrogate to the cross performance in the initial evaluation phase. Data analysis was performed using Griffing's method IV adapted for the available set of crosses to detail the general combining ability (GCA) and specific combining ability (SCA) effects. Significant GCA effects were detected, which demonstrated the possibility of selecting parents based on this parameter. SCA had a higher coefficient of determination than GCA. In conclusion, the selection rate is an effective indicator for evaluation of the combining ability of parents in the first selection stage of a sugarcane breeding program. [ABSTRACT FROM AUTHOR]

The present investigation was conducted at Vegetable Research Farm, Department of Vegetable Science, Punjab Agricultural University, Ludhiana, India. The experimental material comprising of 28 F1 hybrids (made in a halfdiallel fashion excluding reciprocals), eight parental lines and four checks were transplanted in a randomized complete block design with three replications. The σ2SCA:σ2GCA (specific combining ability and general combining ability) ratio suggested that non-additive gene effects had greater role in controlling the inheritance of days to flowering, plant height, fruit length, fruit width, pericarp thickness, total fruit yield, early yield, number of seeds fruit-1, and 100 seed weight. The line SD 463 was found best general combiner for early and total yield. The graphical analysis (Wr/Vr) showed that most of the traits exhibiting partial dominance and over dominance. The cross combination SD 463 × PP 403 was found superior in terms of per se performance, specific combining ability and heterosis over standard checks. Significant and desirable heterosis over better parent and standard checks were recorded for almost all the traits. The present study indicated the preponderance of non-additive gene action involved in the inheritance of studied traits. The presence of parallelism between per se performance, SCA and heterosis suggests the possibility of direct exploitation of these hybrids at commercial level. [ABSTRACT FROM AUTHOR]

Fall armyworm (FAW, Spodoptera frugiperda ) emerged as a major lepidopteran pest destroying maize in sub-Saharan Africa. A diallel mating design was used to generate 210 experimental hybrids from 21 lines. Experimental hybrids and four checks were evaluated in two locations. Commercial checks suffered higher foliar and ear damage compared to the top 15 hybrids. Mean squares associated with the genotypic variation were higher than genotype-by-environment interactions for foliar and ear damage traits. Heritabilities were moderate to high. Significant correlations were observed between grain yield (GY) with ear rot (-0.54) and ear damage (-0.45). Positive and significant GCA effects were observed for GY in seven parental lines, which were developed from multiple insect resistance breeding programmes. CKSBL10153 has the highest GCA value for GY and shows significant GCA effects for foliar and ear damage traits. These lines were identified as the ideal combiners for GY and FAW resistance and are therefore recommended for utilization as testers in the development of FAW-resistant three-way cross-hybrid maize with correlated response for increased GY. GCA and marker-based prediction correlations of GY were 0.79 and 0.96, respectively. Both GCA effects and marker-based models were effective in predicting hybrid performance for FAW resistance., Competing Interests: CONFLICT OF INTEREST STATEMENT The authors declare that there is no competing interest.

Rice ( Oryza sativa L.) is a staple food that feeds over half of the world's population, and the contents of metallic elements in rice grain play important roles in human nutrition. In this study, the contents of important metallic elements were determined by ICP-OES, and included cadmium (Cd), zinc (Zn), manganese (Mn), copper (Cu), iron (Fe), nickel (Ni), calcium (Ca), and magnesium (Mg) in brown rice, in the first node from the top (Node 1), in the second node from the top (Node 2), and in roots of 55 hybrids and their parental lines. The heritability of metallic element contents (MECs), the general combining ability (GCA) for MEC, and the correlation between MECs in different organs/tissues of hybrids were also analyzed. The results indicated that: (1) there was a positive correlation between the contents of Cd and Zn in nodes and roots, but a negative correlation between the contents of Cd and Zn in brown rice of the hybrids(2) the GCA for MECs can be used to evaluate the ability of the parental lines to improve the metal contents in brown rice of the hybrids(3) the contents of Cd, Zn, Ca, and Mg in brown rice were mainly affected by additive genetic effects(4) the restorer lines R2292 and R2265 can be used to cultivate hybrids with high Zn and low Cd contents in the brown rice., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

The objective of this study were to estimate the general ability and specific combining ability in ten wheat genotypes in two generations (F1 and F2) to indicate parents and hybrid combinations that are promising to achieve new favorable combinations. Ten wheat genotypes were hybridized in a complete diallel, without reciprocals, totaling 45 hybrid combinations. F1 hybrids and the F2 populations and parents were evaluated in a randomized block design with three replicates in spaced plant. The effect of general combining ability (GCA) was greater than specific combining ability (SCA) in both generations, regardless of the characters evaluated. The best performances of the CGC to grain yield per plant (GYP), number of kernels per spike (NKS), number of spikes per plant (NSP) and plant height (PH) were observed for the parents Fundacep 50, Pampeano, BRS Figueira and UTF 0605, respectively. Promising hybrid combinations (high magnitude of SCA in both generations and high average for the character and at least one parent presenting desirable GCA) were selected. The association of GCA with the performance of characters GYP (F1 = F2 = 0.75 and 0.81), NKS (F1 = F2 = 0.61 and 0.60) and PH (F1=0.99 and F2= 0.98) showed to be a reliable criterion for choice of parents, regardless of generation evaluated.

To determine the inheritance of bread making quality of bread wheat by diallel crossing, the F1 seeds of a 5 × 5 half diallel along with their parents were grown in water-stress and non-stress conditions, in a randomized complete blocks design, at Islamic Azad University, Ardabil, Iran, in 2009, and 8 characters related to their bread quality along with 1000-seed weight and hectolitre mass were evaluated. The result of combined analysis of variance showed that the effect of stress on protein content, SDS sedimentation volume, wet gluten content, 1000-seed weight and hectolitre mass was significant . The interaction effect of genotype and stress was significant (P

The development of maize foundation parents is an important part of genetics and breeding research, and applying new genetic information to produce foundation parents has been challenging. In this study, we focused on quantitative trait loci (QTLs) and general combining ability (GCA) of Ye478, a widely used foundation parent in China. We developed three sets of populations for QTL mapping and to analyze the GCA for some agronomic traits. The assessment of 15 traits resulted in the detection of 251 QTLs in six tested environments, with 119 QTLs identified through a joint analysis across all environments. Further analyses revealed that most favorable alleles for plant type-related traits were from Ye478, and more than half of the favorable alleles for yield-related traits were from R08, another foundation parent used in southwestern China, suggesting that different types of foundation parents carried different favorable alleles. We observed that the GCA for most traits (e.g., plant height and 100-kernel weight) was maintained in the inbred lines descended from the foundation parents. Additionally, the continuous improvement in the GCA of the descendants of the foundation parents was consistent with the main trend in maize breeding programs. We identified three significant genomic regions that were highly conserved in three Ye478 descendants, including the stable QTL for plant height. The GCA for the traits in the F7 generation revealed that the QTLs for the given traits per se were affected by additive effects in the same way in different populations.

Plasmogenes are largely located in mitochondria or plastids and they can influence the inheritance of many plant characteristics. This phenomenon is called cytoplasmic inheritance and can be detected on the basis of the expression of a trait in progeny F1 obtained from single and reciprocal crosses. The aim of this study was to examine the cytoplasmic inheritance of in vitro productivity of morphogenesis in three genotypes of Fragaria x ananassa Duch., i.e. the cultivars 'Dukat', 'Teresa' and the breeding clone no. 590. Single and reciprocal crosses were done according to Griffi ng's method 3. The value of general combining ability (GCA) indicated cv. 'Teresa' as the best maternal component for crossing and 'Dukat' as the worst. The negative reciprocal cross effects (rij) revealed the cytoplasmic inheritance for cv. 'Dukat' as maternal form and positive rij for the breeding clone no. 590 indicated the nuclear inheritance of morphogenetic ability. Cv. 'Teresa', as maternal component, showed nuclear inheritance of that trait in crossing with cv. 'Dukat' and with 590 cytoplasmic inheritance. The productivity of morphogenesis in strawberry depended on the parental combination and the direction of crossing.

An attempt was made to study the general and specific combining ability in sesame (Sesamum indicum L.) through L X Tanalysis with ten lines and four testers. Eight characters viz., days to 50 per cent flowering, plant height, number of branches perplant, number of capsules per plant, capsule length, number of seeds per capsule, 1000 seed weight and seed yield per plant werestudied. Based on the general combining ability effects of parents IVTS-14-07 [L6] was found to be a good general combiner fordays to 50 per cent flowering and number of capsules per plant, IVTS-215-06 [L10] was found to be good general combiner forplant height, number of branches per plant and 1000 seed weight. IVTS-24-06 [L9] was found to be good general combiner fornumber of seeds per capsule and seed yield per plant. The cross combination IVTS -17-07 X TMV 4 [L5 X T2] showed negative,significant sca for days to 50 per cent flowering. AVTS-3-06 X TMV 3 [L4 X T1] exhibited positive and significant sca fornumber of capsules per plant and seed yield per plant and hence recommended for yield improvement.

Early leaf spot (ELS) is one of the major biotic constraints of groundnut production in West and Central Africa. A study using 6 × 6 F2 full diallel populations from six parents (NAMA, B188, PC79-79, QH243C, TS32-1, and CN94C) was conducted to assess the mode of inheritance of ELS resistance traits. The F2 and parents were grown in a randomized complete block design with three replications. Data was collected on ELS disease severity, and an area under disease progress curve (AUDPC) was estimated. The results revealed that additive and non-additive gene actions were involved in the inheritance of the ELS resistance traits, but additive gene action was predominant. Significant reciprocal cross effect was observed, suggesting cytoplasmic effect on ELS resistance. Graphical analysis also revealed the predominance of additive gene action for ELS resistance. The results suggest that early generation selection should be effective for ELS resistance. Looking at the distribution of array points along with the regression line, parental lines NAMA, PC79-79, and B188 would be suitable as good donors in an ELS disease resistance breeding program.

A Line × Tester analysis in sesame (Sesamum indicum L.) was carried out with seven lines and four testers to estimate the combining abilityeffects, nature of gene action and heterosis for eight characters viz., days to 50 per cent flowering, plant height, number of branches per plant,number of capsules per plant, capsule length, number of seeds per capsule, 1000 seed weight and seed yield per plant. Based on the generalcombining ability effects, IVTS 7 among lines and TMV 6 among testers were found to be good general combiners for seed yield per plant. Thecross combination IVTS 7 X TMV 6 exhibited the maximum positive and significant sca for seed yield per plant and hence recommended forheterosis breeding, whereas the hybrid IVTS-13 × TMV 6 exhibited high test weight and hence it is recommended for breeding bold seeded type.Similarly the hybrid IVTS 8 × TMV 3 recorded desirable sca for earliness

Combining ability in opium poppy, Papaver somniferum L. was analyzed through full diallel cross comprising five parents, 20F1s (including reciprocals) and 20 F2s (including reciprocals). The analysis of variance revealed significant differences for allthe characters demonstrating considerable variation among genotypes. Estimates of components of general and specificcombining ability variances exhibited equal importance of both additive and non additive gene actions for the expression of allthe characters. However, higher magnitude of SCA components of variance indicated preponderance of non –additive effectsfor all the traits except for leaves/plant, seed yield and opium yield in F2 generation. The average degree of dominance wasmore than unity, showed over dominance and also conferred above findings. Among the parents NB-1KR401-3/3 forcapsules/plant, stem diameter, capsule wt/plant, capsule size, peduncle length and seed yield, NB-5KR3-2-2/1 for days to 50%flowering, plant height leaves/plant, capsule wt/plant, and seed yield, Papline and 58/1 for plant height and opium yield andNB-5KR40-7/2/-3 for morphine content were found good general combiners. Inclusion of lines with good GCA in a single ormultiple crosses followed by intermating i.e. population improvement approaches may be expected to offer geneticimprovement in breeding for higher opium, seed yield and its component traits.

The objectives of this work were to identify parents resistant to Asian soybean rust using diallel crosses, obtain information on the genetic control of soybean resistance to the pathogen and verify whether the combining ability estimates interact with the environment (year or time of assessment). The F1 generation was obtained in a greenhouse from crosses between five contrasting parents for the trait resistance to soybean rust, in a complete diallel without reciprocals. Two rust-severity assessments were carried out on individual soybean plants of 25 treatments (parents and F2 and F3 populations) in 2006/2007 and 2007/2008, in an experimental field at Embrapa Soja, Londrina, PR, Brazil. Additive effects predominated in the genetic control of soybean resistance to Asian rust, and the interaction of the segregant populations with the environment, although significant, did not alter the genetic parameter's general combining ability (GCA) and specific combining ability estimates, indicating that estimates obtained in one year and one assessment can be extrapolated to others. BR01-18437 inbred line is resistant to Asian rust and showed high GCA effects. This line should be used as parent if the objective is the resistance to Phakopsora pachyrhizi.Os objetivos deste trabalho foram identificar genitores resistentes à ferrugem asiática da soja por meio de cruzamentos dialélicos, obter informações sobre o controle genético da resistência ao patógeno e verificar se as estimativas da capacidade combinatória interagem com o ambiente (ano ou época de avaliação). A geração F1 foi obtida por meio de cruzamentos entre cinco genitores contrastantes para a característica resistência à ferrugem da soja, em um dialelo completo, sem os recíprocos, em casa de vegetação. Foram realizadas duas avaliações quanto à severidade da ferrugem asiática da soja em plantas individuais de 25 tratamentos (genitores e populações F2 e F3 ) em 2006/2007 e 2007/2008, no campo experimental da Embrapa Soja, em Londrina, PR. Houve predominância de efeitos aditivos no controle genético da resistência à ferrugem asiática da soja, e a interação das populações segregantes com os ambientes, embora significativa, não alterou as estimativas dos parâmetros genéticos da capacidade geral de combinação (CGC) e da capacidade específica de combinação, indicando que as estimativas obtidas em um ano e uma avaliação podem ser extrapoladas para outros. A linhagem endogâmica BR01-18437 é resistente à ferrugem asiática e apresenta alta estimativa de CGC, e deve ser utilizada como genitora quando o objetivo é a resistência a Phakopsora pachyrhizi.