Studies on Genetic Divergence, Inter-relationship and Their Implications in Genetic Improvement of Okra Abelmoschus Esculentus (L.) Moench.) Germplasm

Abstract

The present investigation was carried out with 19 parental line (15 lines × 4 testers) and 60 F1’s were evaluated to assess the variance, genetic parameters, correlation and path coefficient analysis, combining ability and extent of heterosis during Rabi 2017-18. The observations were recorded for 16 characters viz; days to 50%, flowering, days to maturity, plant height (cm), flag leaf area (cm2), productive tillers/plant, spike length (cm), spikelets/spike, biological yield/plant (g), grains per spike, harvest index (%), 1000 grain weight (g), gluten content (%), protein content (%), ash content (%), grain yield/plant (g) and phenol colour reaction (grading). The analysis of variance revealed that there was a highly significant variation present within the genotypes for all the traits. High heritability coupled with the high genetic advance in % of mean was observed for grain yield/plant, biological yield/plant and ash content this indicated that these traits may be relied upon for selection of the genotypes for improvement in wheat. The grain yield/plant showed highly significant and positive correlation with biological yield/plant, harvest index, grains/spike, spike length, ash content, productive tillers/plant and spikelets/spike at both levels. These characters either alone or in combination with yield could be utilized in wheat improvement. Analysis of variance for combining ability revealed that gca variance among lines were found highly significant for all traits, while variance among testers exhibited highly significant for all traits except for gluten content. However, sca variance among crosses due to interaction between F1’s were found to be highly significant for all the characters under study. These findings indicated that both additive and non-additive gene actions played a predominance role in expression of the characters. Hence, the breeding methods such as pedigree, heterosis breeding and biparental mating is suggested for wheat improvement. Ten parents viz., WH 1124, PBW 752, HD 3085, WH 1021, HD 3059, WH 1105, PBW 553, K 9423, PBW 779, DBW 17 and DBW 88 were found to be good general combiners for yield and quality traits. Therefore, these parents may be incorporated in breeding programme. The five best crosses viz., HD 3059 × PBW750, PBW 779 × DBW 88, WH 1021 × PBW 550, DBW 90 × DBW 71 and DBW 16 × DBW 88 showed significant and positive sca effects for grain yield and quality traits. These cross combinations may be exploited in heterosis breeding programme for yield and quality improvement. Thirty eight hybrids were identified as superior over the check variety (PBW 550) and better parent for grain yield. By exploiting these cross combinations through heterosis breeding will lead in enhancing the genetic yield potential in wheat.