Selfing and crossing methods were used to develop the cytoplasmic male sterility (CMS) lines from 2 elite F1 hybrids of CMS hot chilies. The pungency of the CMS lines was improved by backcrossing ...with the B cultivar. The first and second backcrossed progenies of the CMS lines showed significantly higher capsaicin contents than the F1 hybrids. One good female line K16 × BBC2 (K16), was selected and backcrossed with 3 good maintainer cultivars, C5, C9 and C0. Some incomplete male sterility of pollens was demonstrated in the F1 hybrids and the 1st backcrossed progenies while the partial sterility disappeared by the stage of the second and third generations of backcrossing. When K16 and P32 were crossed with restorers, fruit yields and yield components of certain F1 hybrids, parental lines and commercial varieties were significantly different. Heterosis of yield and yield components of the F1 hybrid chilies was significant. When K16 was used as a female parent, positive and significant heterosis of the F1 hybrids was the same as P32. Moreover, significant GCA of the restorer lines, C7, C8 and C9, was observed in some horticultural characteristics. Furthermore, significant differences of the specific combining ability of some characteristics were observed in a few F1 hybrids.
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 less than or equai to 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 x G.86), G.93 x Suvin, and G.86 x 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 x G.86) displayed highly significant specific combining ability impacts. The crosses G.86 x Suvin, Kar x TNB, G.93 x Suvin, and G.93 x 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.
Hybridization is an important breeding method to improve productive traits in aquaculture. The Manila clam Ruditapes philippenarum, a worldwide cultured bivalve, has achieved the great commercial ...success owing to a global appreciation of its delicious taste and affordable price. In order to evaluate the aquaculture potential of clam hybridization, a complete diallel cross between two geographical populations (Shandong and Guangdong) was performed in the present study. Two intra-population mating groups LL (L♀ × L♂) and ZZ (Z♀ × Z♂) and two crossbreeding groups ZL (Z♀ × L♂) and LZ (L♀ × Z♂) were established to investigate the potential heterosis of growth and survival in the clams. Three full-sib families were constructed in each mating group to calculate the growth and survival heterosis. During the larval stage (2 ∼ 10d), no significant difference was detected in averaged shell length between reciprocal hybrids and inbred groups. In contrast, hybrid spats after 15d cultivation showed a significantly larger size (shell length and shell height) than that of inbred spats. For the reciprocal hybrids, the greatest growth heterosis of shell length and height (33.42% and 33.13%) was detected from 20 days after fertilization in ZL. After 40d cultivation, ZL displayed the most growth potential in shell length and height, reaching maximum values of 0.900 and 0.858 mm, respectively. The hybrids had 25% ∼ 40% higher survival rates than those of the inbred groups, with the highest survival heterosis in ZL. The positive values for the general combining ability (GCA) were consistently detected in the Zhanjiang population. At day 40, the special combining ability (SCA) in ZL was approximately two-fold higher than that in LZ. These findings indicate that the hybrids produced by Laizhou males and Zhanjiang females have the greater aquaculture potential, providing a useful crossbreeding strategy for clam genetic improvement in aquaculture.
•Intraspecific crossbreeding of clams produced hybrids with great growth potential.•The growth and survival heterosis were found in larvae and spats.•The greatest growth heterosis was detected at 20d after fertilization.•Crossbreeding of Laizhou males and Zhanjiang females has the great aquaculture potential.
Selfing and crossing methods were used to develop the cytoplasmic male sterility (CMS) lines from 2 elite F1 hybrids of CMS hot chilies. The pungency of the CMS lines was improved by backcrossing ...with the B cultivar. The first and second backcrossed progenies of the CMS lines showed significantly higher capsaicin contents than the F1 hybrids. One good female line K16 × BBC2 (K16), was selected and backcrossed with 3 good maintainer cultivars, C5, C9 and C0. Some incomplete male sterility of pollens was demonstrated in the F1 hybrids and the 1st backcrossed progenies while the partial sterility disappeared by the stage of the second and third generations of backcrossing. When K16 and P32 were crossed with restorers, fruit yields and yield components of certain F1 hybrids, parental lines and commercial varieties were significantly different. Heterosis of yield and yield components of the F1 hybrid chilies was significant. When K16 was used as a female parent, positive and significant heterosis of the F1 hybrids was the same as P32. Moreover, significant GCA of the restorer lines, C7, C8 and C9, was observed in some horticultural characteristics. Furthermore, significant differences of the specific combining ability of some characteristics were observed in a few F1 hybrids.
Quality Protein Maize (QPM) varieties are rich in lysine and tryptophan, but suffer reduced grain yield (GY) in West and Central Africa (WCA) due to low soil nitrogen (low-N) and intermittent drought ...stress (DS). Development of stress-tolerant QPM hybrids will enhance sustainable maize production and improve nutritional health in WCA. Knowledge of combining ability, gene action and heterotic grouping of QPM inbred lines are crucial to successful breeding strategies for the development of superior hybrids with enhanced nutritional values. The objectives of this study were to: (i) determine the combining ability for GY and yield-related traits among 13 newly developed QPM inbred lines, and (ii) assign the QPM inbred lines to distinct heterotic groups based on general combining ability effects of multiple traits under low-N and DS conditions. Seventy-eight single cross hybrids were generated through half-diallel mating of 13 QPM inbred lines and evaluated along with three commercial checks for GY and yield-related traits under the low-N and DS conditions. Significant general combining ability (GCA) and specific combining ability effects were obtained for GY and yield-related traits. Both additive and non-additive gene effects were involved in the inheritance of GY and other traits under low-N and DS conditions. However, the additive gene effect for GY was twice as large as non-additive gene effect. Three heterotic groups were each delineated under low-N and DS. Inbred lines, CRIZEQ-44 and CRIZEQ-77 belonging to different heterotic groups were identified as testers for the development of superior hybrids for low-N and DS environments.
Early maturity and genotype by environment interaction (GEI) have always been challenging concerns for breeders in selecting appropriate parents for breeding programs. The presented study aimed to ...investigate early maturity and the dimension of gene action, as well as, assess the performance of half-diallel populations using eight advanced sweet corn inbred lines and their 28 F1 hybrids with two commercial checks for maturity and yield-related traits in the spring of 2018 at the Nowshera (plain) and Swat (hilly) areas, Khyber Pakhtunkhwa, Pakistan. Analysis revealed significant differences among the genotypes for the studied traits over both locations. General combining ability (GCA) effects were significant for all the traits at both the agro-climatic conditions, except 100-kernel weight, with the specific combining ability (SCA) effects relevant for grain yield at both locations. The GCA-SCA ratio for studied traits indicated dominance gene action, which also gained support by higher values of SCA than GCA variances. Based on the results, the identified inbred lines SWTS-1-8 and SODS-1 serve as good general combiners for traits like earliness and grain yield attributes, making them better parents to improve the stated characteristics in sweet corn. However, the F1 hybrids, i.e., NARCCCRI-19 × CCRI-34 at Nowshera and CCRI-34 × SODS-1 at Swat, showed the best specific combiners for maturity. Likewise, F1 hybrids, i.e., SWTS-1-4 × SWTS-1-8 and SWTS-1-8 × CCRIS-34, emerged as desirable for grain yield at Nowshera and Swat, respectively. The inbred lines for the mentioned hybrids can be a source of germplasm improvement, breaking through undesirable linkages in future sweet corn breeding programs.
Root system architecture is important for common bean (Phaseolus vulgaris) adaptability to diverse environments. Beans employ complex adaptive root mechanisms for coping with multiple stresses in ...production environments. Understanding genetic control of root traits is central to improvement of common bean for adaptation to marginal environments. The objectives of this study were to (i) determine combining ability of root and agronomic traits and (ii) estimate the heritability and genetic correlation of root and agronomic traits in common bean. Four bean lines with superior root traits were crossed with four locally adapted varieties in a North Carolina II mating scheme to generate 16 crosses. The 16 F1s were selfed and advanced to F2 generation. Eight parents and their F2 progenies were evaluated in an alpha‐Lattice design with two replications. General and specific combing ability mean squares were significant (p ≤ .05) for all traits measured. General predictability ratios ranged from .47 to .68 across locations suggesting that both additive and non‐additive gene action modulate root traits and seed yield. Positive and significant (p ≤ .05) phenotypic and genetic correlations revealed significant association between root traits and yield. Moderate to high heritability estimates of between .43 and .67 were realized. Such estimates point to possible deployment of a successful selection programme. Genotype AFR398 displayed significant positive GCA effects among its crosses for both root and agronomic traits hence a potential candidate genotype for inclusion in a bean genetic improvement programme for marginal environments.
Fifty-seven lines of okra including ten parents, forty-five hybrids and two standard checks were evaluated in Randomized Block Design with two replications. Combining ability was carried out to study ...comparisons of lines in combinations for the traits days to 50% flowering, plant height at harvest, the number of branches per plant, the number of nodes per plant, days to first picking, the number of fruits per plant, the mean length of fruit, the mean weight of fruit, yield per plant , yield per plot , yield per hectare and reaction to yellow vein mosaic disease. The result revealed that the variance to general combining ability (gca) is less than specific combining ability (sca), ratio of that is less than unity indicated preponderance of non additive gene action for all the traits. The parent Akola Bahar was good general combiner, whereas, cross combination Shagun x VNR (Super Green) recorded a significant specific combining ability (sca) effects as far as yield is concerned.
PDF