Line × Tester analysis was carried out in a set of 20 crosses developed using five lines and four testers to ascertain the nature of gene action and combining ability of parents for yield, yield ...attributes and quality traits in groundnut. The estimates of GCA and SCA variance indicated the predominance of non-additive gene action for the inheritance of all the traits except SCMR at 60 DAS. The parents TCGS 1694, TCGS 1862, Kadiri-6 and TCGS 2251 were identified as good general combiners which could be further used in breeding programmes for yield improvement. The cross, Kadiri-6 × TCGS 1862 exhibited desirable sca effects for days to maturity, number of secondary branches plant-1, number of pods plant-1, number of mature pods plant-1 and kernel yield plant-1, while the cross Narayani × TCGS 2251 was found to be a good combiner with high sca effects for earliness (days to flowering and days to maturity).These two combinationshad either low × high or high × medium gca parents indicating the involvement of both additive and non-additive gene action.
Prolonged crop duration (150-210 days) and tall plant height (>100 cm) of castor either hinders its adaptability to newer and niche areas or fitting into the cropping sequence of conventional castor ...growing areas. The present study aims at evaluating male lines for their agro-morphological characters, combining ability for seed yield, yield components and resistance to Fusarium wilt. Node number to primary, first and second order of secondary (P, S1 and S2) racemes were taken as indicators of flowering and maturity duration of male lines while data on plant height up to primary spike was recorded for plant stature. Twenty-six improved monoecious lines were evaluated for their agro-morphological characters in an ARBD design along with three checks replicated five times during 2017-18 kharif season. Simultaneously all the 26 lines were screened for wilt resistance in wilt sick plot in two replications. Nineteen monoecious lines were resistant to wilt (0-20% wilt incidence) while four lines were moderately resistant to wilt (20-30%). Four lines viz., ICS-121, ICS-150, ICS-127 and ICS-139 were promising with significantly low node number to P, S1 and S2 order of racemes compared to early maturing check, DCS-9 (12.1, 5.8, 4.9). Eight male lines were significantly shorter than the very tall type checks, 48-1 and DCS-107 (>85 cm) while ICS-121 (57.5 cm) was on par with the medium statured check, DCS-9 (59.7 cm). Fifteen hybrids, generated by crossing three pistillate lines and five selected wilt resistant male lines in a line x tester design were evaluated along with eight parents and two hybrid checks during 2019-20 kharif season. SKP-84 (pistillate line) and ICS-139 (male line) were identified as good combiners for seed yield and majority of the yield components.
Combining ability is a useful tool for choosing appropriate parents, while an understanding of the nature of gene action can help develop effective crop improvement initiatives. In order to study if ...genetic diversity affects hybrid vigour, 50 hybrids were generated by crossing five pistillate lines with ten testers and experimented across two replications during the 2020–21 kharif. Genetic divergence was evaluated as Mahalanobis distance among all potential pairs of lines and testers and also in relation to combining ability. Hybrids were classified into four divergent classes using statistics like distance (D2), overall gca effects among parents, overall sca effects, and midparent heterotic status across crosses. Genetic diversity studies revealed the that parents to be used in hybridization programmes should be moderately divergent, to derive crosses with high better parent heterosis. Hybrids, viz., MCP-1 × ICS-240, MCP-1 × RG-2787, MCP-1 × RG-3160, YRCP-1 × ICS-258, and DPC-22 × RG-2787, were identified as superior to standard checks for economically important traits. Superior male and female base populations can be created through random mating of lines and testers with high breeding values, such as DPC-22, MCP-1, ICP-30, RG-2787, RG-3160, RG-72, and YRC-1904, respectively.
The purpose of this research was to examine the extent of heterosis in 21crosses of bread wheat (Triticum aestivum L.). These hybrids originated from a line x tester mating scheme in which seven ...lines were crossed with three testers. Combining ability analysis revealed that the parental lines HP-25 and HD-3086 performed well for grain yield, while HP-24, HP-22, and HP-06 were observed to be better for other qualities that contribute to yield. Significantly higher positive Specific Combining Ability (SCA) for grain yield per plant was observed for the crosses HP-22 x JAUW-683, HP-44 x HD-3086, and HP-45 x RSP-561 suggesting the role of non-additive gene action. The ratio of variances was observed to be less than unity indicating the presence of non-additive genetic effects in these cross combinations. In terms of heterotic impacts on grain yield, yield contributors, and morpho-physiological features, HP-06 x RSP-561 was shown to be the best combination
Development of rice genotypes possessing high yielding potential; with increased grain iron content is the need of the hour to tackle hidden hunger. Considering the above said fact, genetical ...analysis was conducted in six improved cultivars along with 15 potential crosses thereof. Analysis of variance for combining ability revealed significant differences in GCA and SCA variances for grain yield as well as for iron and zinc content, indicating the possibility of realization of development of iron fortified varieties with higher yielding potential. The preponderance of additive gene action for these two important characters i.e., iron and zinc content indicate that selection will be highly rewarding for genetic improvement pertaining to these two traits. The genotype Gouri was found to be very good combiner for both grain yield (0.93) and iron content of grain (2.04). Similarly, genotype Sebati was found as a very good combiner for both grain yield (0.13) and zinc content of grain (0.65). Some of the superior crosses identified concerning both grain yield and grain iron content were Birupa / Pradeep, Sebati / Gouri, Sebati / Pratap, Gouri / Pradeep and Pratap / Pradeep. Hence, these specific crosses can be used in further breeding programme for the improvement of both grain yield as well as grain iron content. The crosses viz., Bhanja / Pratap and Bhanja / Sebati were found to be superior crosses for both grain yield and grain zinc content.
•Resistance to fire blight is quantitative and shows polygenic inheritance.•Resistance to the disease is transmitted to the progenies by both parents but importance of female parent is greater.•Gene ...interaction of the parental cultivars, effects fire blight-resistance of hybrids.•Use of disease tolerant varieties as female parent in hybridizations ensure more development of disease-resistant genotypes.•Maternal effect influence off ;spring fitness independent of maternal genotype in terms of fire blight resistance.
Fire blight caused by Erwinia amylovora is a serious disease that directly affects pear agriculture and production around the world. The most effective way to struggle with disease is develop new varieties and rootstocks. In this study, for a better understanding of the genetic base of fire blight such as heritability of disease resistance, breeding values of parents and maternal effect were investigated on F1 hybrid pear population. According to results, disease resistance shows polygenic inheritance and multiple factors were effective in heredity. Resistance to disease is transmitted to next generations by both parents. However, the influence of the female parent on inheritance is much greater than pollinator. ‘Magness’ and ‘Mustafa Bey’ varieties were found more effective for the transmission of disease resistance as female parents to next progenies. Similar results were obtained from ‘Kiefer’ and ‘Limon’ as pollinator. In addition to the importance of the parents exclusively in disease resistance, gene interactions between the parents also had a significant effect on this matter. Heritability of fire blight that was calculated from the non-additive genes was 23%, likewise 32% was calculated from additive genes. Broad-sense heritability of fire blight, representing the sum of this two situations was 55%. Maternal gene effects were greater than the pollinator and maternal effect had a 7% effect on the disease resistance, indicating that the cytoplasmic gene effects had important roles in the resistance. Obtained results will form basis for the development of new varieties that become resistant to fire blight by hybridization.
Heterosis is important for improving productive traits in aquaculture, but the heterosis between selected lines remains unclear in bivalve molluscs. Here, a diallel crosses among black shell (B, 7th ...generation), white shell (W, 7th generation) and orange shell (O, 6th generation) lines of the Pacific oyster were performed to examine the potential for exploiting heterosis of productive traits by crossbreeding of selected lines. Heterosis and combining abilities for growth and survival of 27 full-sib families were analyzed at both larval and juvenile stages, of which the juvenile stage was examined at two environments (Rongcheng and Rushan) for 10 months. The variance of specific combining ability accounts for the majority of the total variance for larval and juvenile survival and juvenile growth, which revealed the importance of non-additive genetic effects (heterosis) among these lines. Moreover, all reciprocal hybrids showed low or no heterosis for growth at both larval and juvenile stages, but a high heterosis for larval survival. This finding suggested that inter-line crossbreeding can be applied to improve the larval survival in hatcheries. Furthermore, four of six hybrid crosses showed positive HPH in Rushan but negative HPH in Rongcheng. The higher HPH at Rushan suggested that inter-line crossbreeding in C. gigas has more application value in Rushan. In addition, the survival of both black shell and white shell lines have been improved by crossing with the orange shell line. Especially, the hybrid cross WO (W♀ × O♂) can improve the survival rate of purebred WW by nearly 130% at larval stage and nearly 40% at juvenile stage. Overall, this study reveals the high heterosis for survival among selected lines in the Pacific oyster, and will be helpful for the utilization of non-additive genetic effects among existing selected lines in bivalves.
•The heterosis among selected lines is high in survival but low in growth in C. gigas.•The survivals of all hybrid crosses exceeded their better parental line by 49%–130.56% at larval stage.•The survivals of all hybrid crosses exceeded their better parental line by 8.22%–40.91% at juvenile stage at Rushan.•Shell color, as a natural marker, can simplifies the management of various lines of inter-line crossbreeding in C. gigas.
High-yielding sorghum genotypes with farmer-preferred agronomic traits and durable anthracnose resistance are key drivers of productivity and adoption. The objective of this study was to determine ...combining ability effects and heterosis of selected sorghum lines for yield, yield-related traits, and anthracnose resistance, to identify superior parents and families for further selection and breeding. Nine selected sorghum genotypes with known resistance to anthracnose were crossed, using a 9 × 9 half-diallel mating design. Parents and F
1
families were evaluated across two locations, using a randomized complete block design with three replications. Significant (
P
< 0.01) genotype, location, and genotype × location interaction effects were observed for most traits and anthracnose resistance, indicating mixed performances of the tested genotypes, allowing for further selection. General combining ability (GCA) and specific combining ability (SCA) effects were significant (
P
< 0.01) for most traits, including anthracnose resistance, indicating both additive and non-additive gene action underlying inheritance of the studied traits. Parental genotypes such as Bt-623, 210903, 234112, and 226057 showed positive and significant GCA effects for grain yield. Parents 74222, 214852, and 71708 showed negative and significant GCA for anthracnose resistance. The following families: Bt-623 × 210903, Bt-623 × 234112, Bt-623 × Chemeda, Bt-623 × Gemedi, 210903 × 234112, 210903 × 71708, 74222 × 234112, 74222 × 226057, 234112 × 71708, 226057 × 214852 and 226057 × 214852 expressing positive SCA effects for grain yield were identified. The following desirable families were selected: 174222 × 234112, Gemedi × 71708, Bt-623 × 234112, Bt-623 × Gemedi, 226057 × 71708, Chemeda × 71708, and Gemedi × 71708 with negative SCA effect and low anthracnose severity. These are useful sorghum populations for resistance breeding or direct production.
Bottle gourd Lagenaria siceraria (Molina) Standl. is cultivated for multiple utilities, including as a leafy vegetable, for fresh and dried fruits and seeds. It is an under-researched and -utilized ...crop, and modern varieties are yet to be developed and deployed in sub-Saharan Africa (SSA). There is a dire need for pre-breeding and breeding of bottle gourds for commercialization in SSA. Therefore, this study aimed to determine the combining ability and heterosis among selected genotypes of bottle gourd for fruit yield and related traits under drought-stressed and non-stressed conditions to select the best parents and hybrids. Eight preliminarily selected and contrasting parents with drought tolerance were crossed using a half-diallel mating design. The 8 parents and 28 crosses were evaluated under non-stressed (NS) and drought-stressed (DS) conditions across two growing seasons (2020/21 and 2021/22) using a 6 × 6 alpha lattice design with three replicates. Data were collected on fruit yield and related traits and subjected to analysis of variance, combining ability and heterosis analyses. Significant (p < 0.05) specific combining ability (SCA) and general combining ability (GCA) effects were computed for fruit yield per plant (FYPP). The SCA × environment and GCA × environment interaction effects were highly significant (p < 0.001) for FYPP and SYPP. The results suggest that genetic effects were affected by the test environment. Parental genotypes BG-58 and GC recorded positive and significant GCA effects for FYPP under the DS condition, whereas GC recorded positive and significant GCA effects for FYPP under the NS condition. The two genotypes are ideal breeding parents for population development to select genotypes with high fruit and seed yields. Crosses BG-27 × BG-79, BG-79 × BG-52, BG-79 × BG-70, BG-80 × BG-70, BG-80 × GC, and BG-70 × GC recorded high and positive SCA effects for FYPP and SYPP under DS condition. Crosses BG-81 × BG-52, BG-81 × GC, BG-27 × BG-79, BG-27 × GC, BG-79 × GC, BG-80 × BG-70, BG-81 × BG-58, BG-27 × BG-80, BG-27 × BG-58, BG-79 × BG-52, BG-52 × BG-58, BG-80 × BG-58, and BG-58 × BG-70 recorded high and positive SCA effects for FYPP and SYPP under NS condition. Crosses BG-80 × BG-58, BG-27 × BG-79, BG-79 × BG-52, BG-27 × BG-52, and BG-52 × BG-80 showed high and positive mid- and better-parent heterosis under DS condition for FYPP and SYPP. Crosses BG-27 × GC, BG-79 × GC, BG-27 × BG-58, and BG-27 × BG-79 showed high and positive mid- and better parent heterosis under NS condition for FYPP and SYPP. The newly selected families are recommended for multi-environment evaluation forrelease and commercialization in South Africa or similar agroecologies.
