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Sweet corn breeding goals differ from grain or silage corn. Sweet corn goals focus on marketable yield including several quality traits. This study explores the effect of a single cycle of full‐sib selection and S2 selection on improving the marketable yield of an open‐pollinated sweet corn population. The selected populations were subsequently compared in four environments for several plant‐, yield‐ and quality traits relative to the original population. Analysis of variance was used to detect selection progress and indirect effects of selection. Full‐sib and S2‐selection decreased total yield. Marketable yield was decreased more by S2‐selection than by full‐sib selection. Flowering time was changed by full‐sib selection, but not by S2‐selection. Full‐sib selection improved ear quality by increasing ear length, the diameter of the ear and the number of kernel rows. S2‐selection showed no effect or a negative effect on ear quality. The application of a single cycle of selection using either method seemed inadequate for increasing marketable yield. More cycles might be necessary to make significant improvements. [ABSTRACT FROM AUTHOR]

Differential Evolution (DE) algorithms are widely recognized as effective metaheuristic techniques used to solve continuous optimization problems. However, DE algorithms encounter limitations in exploration and exploitation due to their sensitivity to parameter settings and reliance on mutation strategies. To overcome these drawbacks, we introduced a self-adaptive mutation and population improvement strategy in differential evolution, SAMPIDE. The algorithm adjusts the mutation operator automatically according to the successful mutation operator value from the previous generation. Additionally, to enhance the algorithm’s convergence, we adopted a random learning mechanism to update the population. SAMPIDE was compared with nine state-of-the-art DE variants and four other metaheuristic algorithms across thirty-two benchmark functions. SAMPIDE consistently outperformed others on unimodal, step and noisy functions, while maintaining competitive performance on multimodal functions. Additionally, when tested on five real-world problems, SAMPIDE outperformed other metaheuristic algorithms. Thus, the self-adaptive mutation and population improvement strategy incorporated into SAMPIDE positioned it as a promising solution for a wide range of optimization problems.

Brinjal is one of the most popular vegetables of India and equally widespread throughout the world. However, this crop is affected a lot by various diseases which are the major production constraints and Phomopsis fruit rot and blight is second most devastating diseases of brinjal in India. Development of resistant genotypes is the most economical and environment friendly way to control the disease, for which proper screening of the segregating lines is crucial. For this the F2 line of Muktakeshi × Pant samrat were screened in field conditions. Among the 181 plants producing fruits, Phomopsis fruit rot was observed in fruits of 160 plants, while 21 plants remained immune. [ABSTRACT FROM AUTHOR]

The present study was carried out in 4 seasons during 4 years from 2017 to 2020 at the field of BeniSuef in. Res. Sta., Middle Egypt com. The main objectives were to develop new maize populations of increased tolerance to drought and evaluate predicted and actual gains from one cycle of S1 recurrent selection. Two sets of 121 S2’s were developed from the local population Pop 277, the 1 st set was evaluated under well water (WW) and intermediate water-stress (IWS) conditions. The highest yielding 18 lines (15%) were selected under each environment. Intercrossing of the two groups of 18 S1’s was done in separate blocks. The resulted of new 2 populations, Pop277-IWS and Pop277- WW) indicated wide genetic variation among S1 progenies for most studied traits under all selection environments. Broad sense heritability estimates were generally higher under water-stress than under non-stress conditions. Results indicated that anthesis -silking interval, ears plant-1 and stay green traits could be valuable criteria in increasing the selection efficiency for drought tolerance. Actual superiority in grain yield over Pop277 due to one cycle of S1 recurrent selection was (26.77%) by the improved populations (Pop277-IWS). [ABSTRACT FROM AUTHOR]

True potato seed (TPS) from a bulk-pollinated, long-day adapted, late blight resistant diploid population is being released to the potato breeding community. The population consisted of 72 maternal half-sib families derived from a hybrid population of Solanum phureja-S. stenotomum originally bred for adaptation to long-day conditions in North Carolina, and which subsequently underwent four cycles of selection for resistance to late blight in Pennsylvania; TPS from 58 of these families are being released. The population is segregating widely for early blight resistance and tuber skin color and texture, shape, eye depth, flesh color and specific gravity. TPS has been deposited with the US Potato Genebank in Sturgeon Bay, WI and may be requested from them. [ABSTRACT FROM AUTHOR]

n the present study, by deploying marker assisted recurrent selection (MARS) strategy, the improvement of IR58025B genetic male sterile maintainer population for drought and salinity tolerance was carried out to develop maintainers with drought and salinity tolerance. Individual crosses were performed among sterile plants of IR58025B maintainer population and donors of drought tolerance viz., Vandana (qDTY12.1) and FL478 (Saltol). F1 plants were confirmed for the presence of target genes/QTLs with the help of SSR markers and raised to produce F2 seeds. Selected F2 plants were harvested and seeds from each cross combination were mixed in equal proportions to generate population for the first random mating or recurrent selection cycle. The same process is continued up to 4th cycle and 200 selected plants were subjected to genotyping for drought and salinity with the help of reported SSR markers. About 48 plants were found positive for salinity tolerance, 17 plants were positive for drought and 10 plants were positive for both the traits. These lines were advanced by pedigree method of breeding for deriving maintainers with drought and salinity tolerance.

Wheat (Triticum aestivum L.) breeding programs can take over a decade to release a new variety. However, new methods of selection, such as genomic selection (GS), must be integrated to decrease the time it takes to release new varieties to meet the demand of a growing population. The implementation of GS into breeding programs is still being explored, with many studies showing its potential to change wheat breeding through achieving higher genetic gain. In this review, we explore the integration of GS for a wheat breeding program by redesigning the traditional breeding pipeline to implement GS. We propose implementing a two-part breeding strategy by differentiating between population improvement and product development. The implementation of GS in the product development pipeline can be integrated into most stages and can predict within and across breeding cycles. Additionally, we explore optimizing the population improvement strategy through GS recurrent selection schemes to reduce crossing cycle time and significantly increase genetic gain. The recurrent selection schemes can be optimized for parental selection, maintenance of genetic variation, and optimal cross-prediction. Overall, we outline the ability to increase the genetic gain of a breeding program by implementing GS and a two-part breeding strategy.

Abstract: The objective of this work was to estimate genetic and phenotypic parameters among progenies of the CNA6 population of upland rice (Oryza sativa) for grain yield and plant height in four cycles of recurrent selection, in order to evaluate the genetic variability and the genotype × location interaction. The experimental data were obtained from yield trials of S0:2 progenies, which were carried out in the experimental design of Federer’s augmented blocks, without replications for progenies within each location. The effect of S0:2 progenies was significant in all cycles for grain yield and in the first three cycles for plant height, indicating the maintenance of the population’s genetic potential to generate transgressive progenies. The participation of the component of the progeny × location interaction in phenotypic variance was of high magnitude. The genetic variability of the CNA6 population of upland rice is maintained for grain yield and plant height during the four cycles of recurrent selection.

Breeders need a simple and reliable index that could be used to make selection quickly in a breeding program. A study was conducted at the International Institute of Tropical Agriculture, Nigeria, to compare efficiency of four selection indices in selecting the best genotypes in a population improvement program involving a yellow-grained (DMR ESR-Y) and white-grained (DMR ESR-W) maize (Zea mays L.) population under artificial stem borer infestation. Rank summation index (RSI), Base index (BSI), Multiplicative index (MI), and Optimum index that uses heritability as weight (OI) were compared using grain yield, plant aspect, ear aspect, stalk breakage, and tolerance to stem borer as selection criteria. The selection criteria had moderate to high narrow-sense heritability. Each of the traits had a significant correlation with all selection indices, except MI in DMR ESR-Y. The BSI had the highest selection differential (23.32%) followed by OI (21.45%) in the white maize population. It also had the highest (29.11%) followed by RSI (20.99%) in the yellow maize population. The BSI also had strongest correlation with RSI in the white (−0.95**) and the yellow maize population (−0.90**). Percentage similarity was highest between BSI and RSI in the white (82.6%) and yellow maize populations (72.3%). This suggested that both BSI and RSI are good selection indices that could be used in improvement programs for stem borer resistance in maize. [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.)

Increasing levels of foliar resistance to late blight, caused by Phytophthora infestans, have previously been reported through two cycles of recurrent maternal half-sib selection in a diploid hybrid population of Solanum phureja-S. stenotomum. The objective of this study was to determine if continued improvements for resistance to late blight could be realized by another cycle of selection. Four clones from each of 72 maternal half-sib families constituting the cycle four population were evaluated for late blight resistance in replicated field trials in Pennsylvania in 2015 and 2016. The experimental design was a randomized complete block design with two replications each year. P. infestans US23 genotype was used in inoculations each year. Area under the disease progress curve (AUDPC) was calculated based on visual assessment of foliar disease five times late in the season each year and subjected to statistical and genetic analyses. Mean AUDPC in the cycle one, two, three, and four populations was 652, 556, 276, and 173, respectively. Narrow-sense heritability for resistance decreased in the cycle four population (h2 = 0.54) as compared to prior populations (0.77 ≤ h2 ≤ 0.80), however, broad-sense heritability remained high (H = 0.83). Additional improvements for late blight resistance are likely to occur if this approach is continued. [ABSTRACT FROM AUTHOR]

Improvement of anthocyanin levels in husks and cobs of field corn may add economic value to corn coproducts in commercial production. This study aimed to evaluate the response to four cycles of modified mass selection (MMS) for yield, agronomic traits, total anthocyanin yield (TAY), total anthocyanin content (TAC), total phenolic content (TPC) and antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity assay (DPPH) and trolox equivalent antioxidant capacity assay (TEAC) in corn husk and cob of five purple field corn populations. The improved populations and check varieties were evaluated at two locations for two seasons in 2017/2018. Selection cycle contributed to a large portion of the total variations for TAC, TPC, DPPH and TEAC in corn husk and cob. All tested populations showed progress for days to anthesis, TAY, TAC, TPC, DPPH and TEAC across four cycles of selection. Lack of significant correlation between agronomic traits and anthocyanin concentrations suggested the independent segregation of these traits. MMS was successfully used to develop field corn populations with improved anthocyanin, antioxidant activities and early flowering without significant yield loss. The populations with the highest selection gains for anthocyanin in husk and cob were identified. Visual selection for dark purple husks and cobs boosted anthocyanin levels and antioxidant activity in selected populations.

With the adverse effects of climate change, selecting the best tolerant varieties to drought stress is highly necessary to sustain the yield and productivity of agricultural crops including tree crops. However, classical drought tolerance selection studies of tree crops have several limitations due to their relatively long lifespan. In this study, we propose a method to identify stable high-yielding trees under changing soil moisture conditions using yield data of existing elite tree populations. We develop this method using the data from a tropical tree palm, Coconut ( Cocos nucifera L.) as a model crop. Our selection method considers individual palms as different genotypes. The method considered both mean trait values and their stability across different environments therefore, it can be effectively used to identify elite genotypes of tree crops for drought tolerance.•We propose an analysis framework to identify stable, high-yielding individuals of tree crops under limited soil moisture conditions using the data of existing tree populations.•Individual trees that produce stable and higher yields under soil moisture stress were identified based on mean yield and regression-based coefficient over different environments characterized by inter-annual rainfall variability.•Individual trees selected by this method can be used as parental populations in breeding programs that focus on developing drought-tolerant varieties., 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 Author(s).)

Maize (Zea mays L.) is one of the crops in which the genetic variability has been extensively studied at isoenzymatic loci. The genetic variability of the maize populations BR-105 and BR-106, and the synthetics IG-3 and IG-4, obtained after one cycle of a high-intensity reciprocal recurrent selection (RRS), was investigated at seven isoenzymatic loci. A total of twenty alleles were identified, and most of the private alleles were found in the BR-106 population. One cycle of reciprocal recurrent selection (RRS) caused reductions of 12% in the number of alleles in both populations. Changes in allele frequencies were also observed between populations and synthetics, mainly for the Est 2 locus. Populations presented similar values for the number of alleles per locus, percentage of polymorphic loci, and observed and expected heterozygosities. A decrease of the genetic variation values was observed for the synthetics as a consequence of genetic drift effects and reduction of the effective population sizes. The distribution of the genetic diversity within and between populations revealed that most of the diversity was maintained within them, i.e. BR-105 x BR-106 (G ST = 3.5%) and IG-3 x IG-4 (G ST = 4.0%). The genetic distances between populations and synthetics increased approximately 21%. An increase in the genetic divergence between the populations occurred without limiting new selection procedures.

A random mating population of Indian mustard [Brassica juncea (L.) Czern. & Coss.] utilizing 20 germplasm accessions/promising donors for component traits, was developed from 2007-08 to 2009-10. Single plant progenies (180) termed as ‘half sibs’ were developed from this population and evaluated during 2010-11 in augmented block design along with standard checks. Observations were recorded on siliquae/ plant, siliquae length, seeds/siliqua, seed yield/plant and 1000-seed weight. The estimates of heritability were observed to be high 59.16 to 97.94% for all the characters. High heritability coupled with high genetic advance and GCV were observed for siliquae/plant and seed yield/plant. Maximum number of half sib progenies showed significant superiority for 1000 seed weight (39.44%) followed by seed yield/plant (10.55%), siliquae length (5.5%), siliquae/plant (5%) and seeds/siliqua (1.66%). These progenies may be utilized for initiation of second cycle of selection/development of trait specific gene pools.

Trees are important sources of food, fibre, fodder, fuel, and timber. Fruit and forest trees provide habitat for wildlife, sequester carbon, and protect soil and water resources. Despite a very long history of domestication of some fruit tree species, such as apple, domestication and breeding of many tree species is still in their early stages. The domestication of trees can be accelerated by modern tree breeding practices. Advances in genomic technologies are providing valuable tools to tree breeders. Breeders can be more efficient in improving the traits of interest to increase productivity, and develop genetic resources that can adapt to changing environment and have resistance to disease and pests. In this chapter, we first briefly examined the current status of major forest (conifers, eucalypts) and fruit trees (apple, peach, pear) breeding across the world. We then described the breeding strategies employed to improve the populations. A summary of genomic resources available for major tree species is also covered. The challenges and opportunities of genomic selection applications are finally summarized. [ABSTRACT FROM AUTHOR]

Copyright of Minufiya Journal of Agricultural Research 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.)

Foliar late blight, caused by Phytophthora infestans, is an important disease problem worldwide. Foliar resistance to late blight was found in a hybrid population of the cultivated diploid species Solanum phureja-S. stenotomum ( phu-stn). The objective of this study was to determine if resistance to late blight could be improved by recurrent maternal half-sib selection in the phu-stn population. Four clones from each of 72 maternal half-sib families plus the check cultivar 'Atlantic' were evaluated for late blight resistance in replicated field trials in Pennsylvania. The most late blight resistant clone from each of the 72 families was randomly intermated to advance the population. The cycle 1, 2, and 3 populations were evaluated in 1996-1997, 2003-2004, and 2009-2010, respectively. Percent infected foliage was recorded several times towards the end of the growing season and used to compute area under the disease progress curve (AUDPC). Mean AUDPC was 652 (cycle 1), 556 (cycle 2), and 276 (cycle 3), whereas the mean AUDPC of 'Atlantic' ranged from 775 to 863 each cycle. Narrow-sense heritability for resistance was estimated as 0.78, 0.77, and 0.80 in cycles 1, 2, and 3, respectively. Recurrent maternal half-sib selection continues to improve the levels of resistance to late blight in this diploid population with no adverse effect on the amount of additive genetic variance. Additional improvements for late blight resistance are likely to occur if this approach is continued. [ABSTRACT FROM AUTHOR]

Highlights: [•] Mass selection raised pyrethrin content from 1.37% to 1.69% in progeny population. [•] Pyrethrin content of progeny population improved even more to 1.87% by polycross. [•] Family selection did not improve pyrethrin content. [•] Mass selection and polycross increased the frequency of desirable individuals in populations. [•] Polycross is more effective for the rapid improvement of pyrethrum populations. [ABSTRACT FROM AUTHOR]

The objectives of this study were to evaluate the response to modified mass selection for long ears of a waxy corn population, Khon Kaen Composite #1, and to investigate correlations between ear length and yield and other important traits. Five cycles of modified mass selection for ear length were evaluated in the rainy season of 2011 and the dry season of 2011/12. A randomized complete block design with four replications was used in this study. Five cycles of modified mass selection could increase ear length from 17.7 cm to 19.3 cm, and the selection gain per cycle was 0.39 cm. The correlation coefficient between ear length and unhusked ear yield was positive and significant (r = 0.85**); that between ear length and husked ear yield was also positive and significant (r = 0.50**). The results indicate that selection for ear length could increase ear yield in Khon Kaen composite #1 population. The improved population can be released as an open-pollinated variety and used as a germplasm source for yield improvement in waxy corn. [ABSTRACT FROM AUTHOR]

To study the effectiveness of recurrent selection in population improvement of rapeseed variety, a recurrent selection population was constructed by mixing several germplasm populations with high - yield, double -low and disease - resistant characteristics, using dominant genic male sterile line as a bridge for random mating. This recurrent population was then subjected to consecutive selections mainly on yield, quality and Sclerotinia stem rot resistance. Results showed that, after 6 selection cycles on the population, seed yield increased by 11. 3% with a genetic gain of 1. 88% per cycle. Except for stem rot resistance, obvious genetic improvements were found in erucic acid and glucosinolates contents, with a respective genetic gain of 10. 12% and 6. 37% . The population genetic dispersion was stable and high (from 0. 338 3 to 0. 377 7), indicating no obvious penalty on genetic diversity after several cycles of selection. Ideal fertile plants identified in different generations were further developed into breeding lines by pedigree selection method. A number of new cultivars (i. e. Zhongshuang 5, Zhongshuang 6 and Zhongshuang 10) had been released and widely distributed, indicating that the recurrent selection is very useful to improve rapeseed population. [ABSTRACT FROM AUTHOR]

Abstract: Population improvement is a basis of germplasm enhancement and developing inbred lines in maize (Zea mays L.). For evaluating the combing abilities of Yuzong 5 developed populations derived from 5 cycles of recurrent selection, 30 testcrossing combinations were made using Huangzao 4, Dan 340, Zhongzong 5, Qi 319, Ye 478, and Mo17 as the female parents in 2 locations under the NCII design. The yield per plant of testcrossing combinations was enhanced by 3.57% per cycle, showing a remarkable effect of recurrent selection. Both half-sib recurrent selection (HS-RS) and half-sib reciprocal recurrent selection (HS-RRS) were effective for improving the general combining ability (GCA) of kernel yield and the GCA was improved in each cycle of the populations. After 3 cycles of improvement in Yuzong 5 by HS-RS, the GCA significantly increased from (11.63 of C0 to 5.57 of C3 population (P < 0.01). After 1 cycle of improvement by HS-RRS, the GCA increased from 5.57 of C3 to 9.75 of C4 population. The specific combining ability (SCA) of improved Yuzong 5 × Huangzao 4 was enhanced, which indicated an approaching Reid × SiPT heterotic pattern during Yuzong 5 improvement cycle by cycle. [Copyright &y& Elsevier]

During the last 100 years, in Western Europe and elsewhere, considerable effort has been devoted to improving perennial ryegrass (Lolium perenne L.) for agriculture. The first persistent cultivars to be widely used were more digestible than other common pasture species but were no higher yielding than the better wild populations of perennial ryegrass. Two main approaches (here called mainstream breeding and population improvement) have been used to further improve the species for the UK, but no recent experiments to assess progress have been published. In 2006, two plot trials were established at IBERS to compare the performance of some newer cultivars and candidate varieties with the first persistent cultivars to be widely used in the UK. One trial involved comparing 10 intermediate-heading (6 diploid and 4 tetraploid) cultivars and candidate varieties with the intermediate-heading cv. Talbot, and the other involved comparing 11 late-heading (4 diploid and 7 tetraploid) cultivars and candidate varieties with the late-heading cv. 23. During 2007 to 2009, one silage cut and 6 other cuts were harvested each year, annual dry matter (DM) yields were determined and DM samples analysed for in vitro DM digestibility (DMD), water soluble carbohydrate (WSC) and crude protein (CP) concentrations in the DM. Percentage ground covered by perennial ryegrass in November 2009 was estimated visually. Twenty of the 21 cultivars were significantly (12 to 38%) higher yielding, 15 were significantly (10 to 27 g/kg) higher in mean DMD, 15 were significantly (25 to 58 g/kg) higher in mean WSC and 7 (all diploids) were significantly higher in ground cover in autumn of the third harvest year than their respective control cultivars. There were no significant differences among the varieties in mean CP over all harvests. The newest intermediate heading cultivar (the diploid Abermagic) produced 29% more DM, was 10 g/kg higher in DMD and 51 g/kg higher in WSC, and had significantly better ground cover at the end of the third harvest year than Talbot. The newest late-heading cultivar (the tetrapioid Aberbite) produced 28% more DM than S23 and was 22 g/kg higher in DMD and 58 g/kg higher in WSC, although it was similar to 23 for ground cover at the end of the third harvest year. Both of these new varieties were developed entirely or partly by population improvement at IBERS over 26 years (1980 to 2005). These results suggest that the rates of gain in DM yield under nitrogen-limiting conditions and in herbage WSC concentration from perennial ryegrass breeding can be improved by utilizing new technologies and better breeding strategies. [ABSTRACT FROM AUTHOR]

Abstract: For evaluating the effects on improvement of different maize (Zea mays L.) synthetic populations, genetic parameters derived from simple sequence repeat (SSR) markers were statistically analyzed with maize synthetic populations GP3, GP4, and GP5 after 4 cycles of mass selection. Genetic differences were observed in most traits across populations or cycles, and the interaction between population and cycle was significant. The genetic gains ranked as GP3 < GP5 < GP4 for kernel depth and as GP3 > GP5 > GP4 for row number per ear. Means of kernel depth and row number per ear were obviously increased after 4 cycles of mass selection, showing significantly direct responses to selection. Plant height and ear height were enhanced by selection, and the increment in GP4 was significantly higher than that in GP3 and GP5. The genetic gains of yield per plant and ear diameter were higher in GP4 than in GP3 and GP5. In all populations, most yield traits were improved in cycle C4 compared to those in cycle C0, showing a significant correlated response. Except for plant height and ear height, the other traits showed significant variations in GCA, and the GCA effects of GP5 in most yield traits were higher than those of GP3 and GP4. In most yield traits, the GCA effects tended to increase with the progress of population improvement through mass selection. Testcross combinations with yield per plant more than 8% over the controls were derived from the cycle C4, showing a significantly indirect response to mass selection. The variation coefficients of phenotypic traits varied slightly across selection cycles. The genetic similarity based on SSR data showed slight increases in GP3 and GP4, but relative stability in GP5. With the increase of selection cycle, the genotype number in derivatives had small reductions in GP3 and GP4, but an increase tendency in GP5. These results indicate that mass selection is not only effective for population improvement but also maintained the genetic diversity of the population. The effect of genetic improvement varied across populations of traits. [Copyright &y& Elsevier]

Seventy-two potato cultivars have been bred at the Scottish Plant Breeding Station and the Scottish Crop Research Institute since 1920. The original genetic base contained resistance to wart disease and to viruses, but not comprehensive resistance to all strains. Introgression of resistance genes from the wild and cultivated potato species of Latin America started for late blight in 1932, for viruses in 1941 and for potato cyst nematodes in 1952. Just seven of the 219 wild tuber-bearing species recognized by Hawkes in 1990 feature in the pedigrees of our cultivars, with Solanum demissum for blight resistance in 58, S. vernei for nematode resistance in 19 and S. microdontum for Potato virus Y resistance in 15, the other four species being S. multidissectum, S. commersonii, S. maglia and S. acaule. Resistance to other fungal and bacterial diseases has been mainly due to chance rather than deliberate breeding. From 1970, selection for yield and quality included processing quality, and despite lack of commercial success, prospects remain good for cultivars resistant to sweetening during cold storage. Since 1990 prebreeding has combined desirable traits through efficient recurrent selection based on progeny testing and provided parents for the commercially funded breeding of finished cultivars. Only one cultivar is a Neotuberosum–Tuberosum hybrid, whereas 15 cultivars have the H1 gene for resistance to Globodera rostochiensis introgressed from group Andigena. Long-day Phureja cultivars are finding a market niche for their flavour attributes. Breeding strategies and methods are critically reviewed from a genetic viewpoint. [ABSTRACT FROM AUTHOR]

Wheat (Triticum aestivum L.) breeding programs can take over a decade to release a new variety. However, new methods of selection, such as genomic selection (GS), must be integrated to decrease the time it takes to release new varieties to meet the demand of a growing population. The implementation of GS into breeding programs is still being explored, with many studies showing its potential to change wheat breeding through achieving higher genetic gain. In this review, we explore the integration of GS for a wheat breeding program by redesigning the traditional breeding pipeline to implement GS. We propose implementing a two-part breeding strategy by differentiating between population improvement and product development. The implementation of GS in the product development pipeline can be integrated into most stages and can predict within and across breeding cycles. Additionally, we explore optimizing the population improvement strategy through GS recurrent selection schemes to reduce crossing cycle time and significantly increase genetic gain. The recurrent selection schemes can be optimized for parental selection, maintenance of genetic variation, and optimal cross-prediction. Overall, we outline the ability to increase the genetic gain of a breeding program by implementing GS and a two-part breeding strategy. [ABSTRACT FROM AUTHOR]

Copyright of American Journal of Potato Research is the property of Springer Nature 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.)

Six pearl millet (Pennisetum glaucum [L.] R. Br.) composites were subjected to three or more cycles of selection in multilocational yield trials and downy mildew disease nurseries in India. The base and selected populations were tested (a) over four years at three locations in India (11° to 29°N), (b) under terminal-drought and optimal moisture conditions for two years, and (c) under induced downy mildew infections to determine the impacts of selection on grain yield, agronomic traits, and resistance to downy mildew (Sclerospora graminicola Sacc. Schroet.). Mean grain yield increases for four composites undergoing three to six cycles of selection ranged between 23 to 94 kg ha[SUP-1] cycle[SUP-1] (0.9 to 4.9 % cycle[SUP-1] ) which, averaged over composites, amounted to 3.3 % cycle[SUP-1] . Yield gains were generally expressed at all test locations and under both terminal-drought and optimal moisture environments. The gains in grain yield were associated with increases of both biomass and harvest index without extending the growth duration except in the earliest composite. Susceptibility to downy mildew remained below 10 % in all selected populations. Thus, the effectiveness of recurrent selection for increasing yield and yield stability of pearl millet is clearly demonstrated. [ABSTRACT FROM AUTHOR]

The possible applications of genic male sterility (GMS) in plant breeding are reviewed and discussed. The basic contribution of GMS is that it provides a means of genetic emasculation which can be applied for the massive production of hybrids. There are two main fields of application: (1) the production of hybrid varieties and (2) inter- and intraspecific hybridization and back-crossing programmes for the introduction of genetic variation into crop varieties. Several schemes have been proposed for using GMS in hybrid breeding in different crops. These are discussed under four headings: genetic methods, cytogenetic methods, temporary restoration of fertility and manual pollination. The application of GMS in hybridization intended for the introduction of alien genes is discussed as well as factors affecting the pollination of genic male steriles. [ABSTRACT FROM AUTHOR]

Two maize ( Zea mays L.) populations, AS1(S) and ECR-A, were evaluated for allozyme frequency changes associated with selection for improved seedling emergence, early season vigor and early maturity. Eleven marker loci were examined and four loci were used for indirect selection in an attempt to modify cold tolerance and maturity. Allozyme-selected divergent subpopulations were produced by compositing selected S progeny from cycle one (C1) of AS1(S) and from C2 of ECR-A. These subpopulations and S generations from all cycles resulting from phenotypic selection, ECR-A C1 through C7 and AS1(S) CO through C6, were tested in cold tolerance and agronomic performance trials over five environments in 1986. Seedling emergence and seedling dry weight did not improve with phenotypic selection in ECR-A, while plant height, ear height, grain yield, grain moisture, days to mid-silk and days to mid-pollen were reduced significantly. Contrasts between divergent allozyme-selected subpopulations from ECR-A were significant for grain moisture and mid-pollen date. For AS1(S), seeding emergence increased, while plant and ear height decreased with phenotypic selection. Contrasts between allozyme-selected subpopulations were significant for plant and ear height. Changes associated with marker-based selection for AS1(S) were not in the same direction as with phenotypic selection. Selection for favorable allozyme genotypes may be effective in changing certain traits in populations that have been modified by direct selection, however results may not be predictable. [ABSTRACT FROM AUTHOR]

Univariate and multivariate analyses were used to identify associations between eight enzyme marker loci and 11 quantitative traits of maize ( Zea mays L.). The material analyzed included inbred lines Wf9 and Pa405, single-cross hybrid Wf9 X Pa405, and the F2 generation of the selfed single-cross hybrid. Each enzyme locus assayed was associated with at least one quantitative trait, and all quantitative traits were associated with genotypes at particular enzyme loci. Significant associations also were found between the level of heterozygosity per individual and nine of 11 quantitative traits. The total contribution to heterosis, for seed yield per plant, of genes linked with the eight enzyme loci, was 27% of the F2 mean and 18% of the difference in mean between the F1 hybrid and the inbred parents. Genes linked with Glu1 accounted for nearly one third of the total dominance effect detected by the eight enzyme loci. The chromosome segments marked by loci with significant effects on seed yield were markedly overdominant. The large heterotic effects of chromosome segments marked by particular loci suggest that enzyme loci could be used to help transfer genes responsible for heterosis to inbred lines. We conclude that analyses of additional inbred lines, F1 hybrids, and F2 populations in more environments will halp identify specific associations between enzyme loci, or chromosome segments which they mark, and important agronomic traits. [ABSTRACT FROM AUTHOR]

Three recurrent selection schemes suitable for kale ( Brassica oleracea L.), involving half-sib (HS), full-sib (FS) and selfed (S) families, were compared by computer simulation. All combinations of 6, 12 and 24 families selected, out of 120 and 240 assessed, were investigated for a range of genetical models. Selection was simulated for 20 generations from an initial allele frequency of 0.05 and for 16 generations from an initial frequency of 0.20. With an initial frequency of 0.05 there was a serious loss of desired alleles ranging from 0.31 out of 20 for the HS scheme with 24 out of 240 families selected to 9.19 for the S scheme with 6 out of 120 families selected. It was concluded that if as many as 20 cultivars were included in the initial population the selection scheme should be chosen to minimise the loss. With an initial frequency of 0.20 there were no losses with 12 and 24 families selected in the HS and FS schemes respectively, and the highest loss was 2.88 for the S scheme with 6 out of 120 families selected. It was concluded that if as few as five cultivars were included in the initial population a compromise between the initial response to selection and the loss of desired alleles should be sought. Selecting 6, 12 and 24 families for the HS, FS and S schemes respectively, resulted in average relative responses per generation of 2.28, 2.74 and 2.76, respectively for the first five generations, and losses of 0.22, 0.13 and 0.35, respectively after 16 generations. Practical considerations favour the FS scheme over the S scheme. [ABSTRACT FROM AUTHOR]

It is shown here that genetic advance in one cycle of recurrent selection can be formulated directly in terms of covariances between relatives by application of the general statistical principle of linear prediction. For practical use of such formulae it is necessary to estimate the corresponding covariance between relatives from the mating design used. With General Combining Ability selection such estimation is direct. For other types of selection, it is necessary to derive associated covariances from other types of covariances but it is not necessary to use classical results of covariances between relatives in terms of genetic effects. Indeed, covariances can be derived without factorial decomposition of the genetic effects at one locus, i.e., without the concept of additivity and dominance. This approach allows a simple derivation of the genetic advance after n cycles of selection, followed by m generations of intercrossing, with a minimum of assumptions. [ABSTRACT FROM AUTHOR]

Improvement of anthocyanin levels in husks and cobs of field corn may add economic value to corn coproducts in commercial production. This study aimed to evaluate the response to four cycles of modified mass selection (MMS) for yield, agronomic traits, total anthocyanin yield (TAY), total anthocyanin content (TAC), total phenolic content (TPC) and antioxidant activity determined by 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity assay (DPPH) and trolox equivalent antioxidant capacity assay (TEAC) in corn husk and cob of five purple field corn populations. The improved populations and check varieties were evaluated at two locations for two seasons in 2017/2018. Selection cycle contributed to a large portion of the total variations for TAC, TPC, DPPH and TEAC in corn husk and cob. All tested populations showed progress for days to anthesis, TAY, TAC, TPC, DPPH and TEAC across four cycles of selection. Lack of significant correlation between agronomic traits and anthocyanin concentrations suggested the independent segregation of these traits. MMS was successfully used to develop field corn populations with improved anthocyanin, antioxidant activities and early flowering without significant yield loss. The populations with the highest selection gains for anthocyanin in husk and cob were identified. Visual selection for dark purple husks and cobs boosted anthocyanin levels and antioxidant activity in selected populations. [ABSTRACT FROM AUTHOR]