Heterosis and heterobeltiosis in bell pepper (Capsicum annuum var. grossum) for growth and yield parameters

The magnitude of heterosis over commercial check and better parent was estimated to identify best crosses for growth and yield traits in bell pepper. Experimental material included 21 F1 hybrids developed by crossing seven diverse parents in half diallel mating design. The findings revealed that Arka Mohini X CW308 showed best heterotic cross combinations, recorded significantly higher heterosis and high per se value over commercial check with respect to number of primary branches, number of secondary branches, plant height, days to 50% flowering, days to first harvest, fruit length, fruit width, number of lobes per fruit, number of fruits per plant and average fruit weight. The cross Arka Mohini X CW308 also showed high heterobeltiosis for traits like fruit length, number of fruits per plant, average fruit weight and average yield per plant. Hence, this hybrid with high per se value and heterosis can be utilized to obtain desirable segregates for development of superior genotype for improvement of horticultural traits in bell pepper

Variability and genetic diversity among selfed lines (S1) of onion (Allium cepa L.)

Onion is a highly cross-pollinated crop, high variability could possibly come from traditional seed production by out-crossing or by open pollination and it could lead to more diversity and variation. The high phenotypic, genotypic variation coefficients reveal high-quantifiable variation of traits in S1 lines. Selection of lowest premature bolting and split bulbs producing genotypes, least incidence of purple blotch incidence and thrips incidence with the highest weight of ten bulbs and maximum plot yielding genotypes were more appropriate for genetic improvement of onion. The traits aided the yield witnessed high traits heritability (h2) and maximum genetic-advance-mean (GAM) and isolation of S1 lines in terms of selection indices fixed for higher values of measurement. Whereas traits like premature bolting, split bulbs, purple blotch incidence, thrips incidence and were selected at least values although these traits were high heritability (h2) and GAM could contribute for additive-gene-action and hence it indicates the straight mass selection be more effective for genetic improvement of onion genotypes or lines. The genetic distance was highly flanked by Cluster-II and –IV groups and was highly divergent. Hence, the selection of parental lines from these groups is more appropriate for traditional heterosis breeding

Variability and genetic diversity among selfed lines (S1) of onion (Allium cepa L.)

563-568Onion is a highly cross-pollinated crop, high variability could possibly come from traditional seed production by out-crossing or by open pollination and it could lead to more diversity and variation. The high phenotypic, genotypic variation coefficients reveal high-quantifiable variation of traits in S1 lines. Selection of lowest premature bolting and split bulbs producing genotypes, least incidence of purple blotch incidence and thrips incidence with the highest weight of ten bulbs and maximum plot yielding genotypes were more appropriate for genetic improvement of onion. The traits aided the yield witnessed high traits heritability (h2) and maximum genetic-advance-mean (GAM) and isolation of S1 lines in terms of selection indices fixed for higher values of measurement. Whereas traits like premature bolting, split bulbs, purple blotch incidence, thrips incidence and were selected at least values although these traits were high heritability (h2) and GAM could contribute for additive-gene-action and hence it indicates the straight mass selection be more effective for genetic improvement of onion genotypes or lines. The genetic distance was highly flanked by Cluster-II and –IV groups and was highly divergent. Hence, the selection of parental lines from these groups is more appropriate for traditional heterosis breeding

MULTIVARIATE ASSESSMENT OF YIELD AND ITS COMPONENTS IN OKRA [Abelmoschus esculentus (L.) Moench] GENOTYPES

Not AvailableOkra [Abelmoschus esculentus (L.) Moench] is a valuable vegetable in many regions of the world, especially in the tropics and sub-tropics. It is not only a nutrient-rich vegetable but also an important medicinal herb (Yuan et al., 2014). Although India is the largest producer of okra with 6.35 million tonnes production (72.9% of total world production) from 0.53 million hectare area (Anonymous, 2015), its productivity potential is low. A major constraint in okra productivity is the low genetic potential of the present okra varieties. Improvement of okra requires a broad spectrum of genetic variability from which useful characters can be selected for developing broad-based populations to be used in hybridization programme (Lester et al., 1990; Hammond and Charrier, 1983). Genetic distance estimates form the basis for selecting parental combinations. Genetic distance estimates for population can be estimated by different methods. One of the approaches is to apply multivariate analysis as it has extensive use in summarizing and describing the inherent variation among crop genotypes. Multivariate statistical tools include Mahalanobis D2 analysis, cluster analysis, principal component analysis (PCA) and discriminate analysis (Oyelola, 2004). Mahalanobis D2 multivariate analysis (Mahalanobis, 1936) for obtaining quantitative estimates of genetic divergence and Tocher’s method for grouping of different genotypes of a particular crop are more valuable tools in choosing suitable parents for heterosis breeding. PCA can be used to uncover similarities between variables and classify the genotypes. With this backdrop, an attempt was made in the present study to assess the nature and magnitude of genetic divergence of some okra genotypes consisting of advanced breeding elite lines developed at Indian Institute of Horticultural Research (IIHR), Bangalore using various multivariate analysis tools.Not Availabl

Exploitation of Hybrid Vigour and Combining Ability Studies for Yield and Its Attributing Traits in Ridge Gourd [Luffa acutangula (Roxb.) L.]

Twelve parental lines (7 lines and 5 testers) were crossed in Line × Tester mating design and 35 F1 hybrids of ridge gourd obtained and were studied to investigate the extent of heterosis and combining ability for yield and related traits. Result revealed that the crosses, COHB-1 × Deepthi (25.95 %), COHB-33 × Deepthi (11.07 %) and COHB-32 × Pusa Nutan (5.09 %) exhibited maximum and significant positive heterosis over the commercial check (Naga) for fruit yield per vine. Among the parents, maximum and significant gca effects was recorded in the line COHB-33 (0.66) followed by Pusa Nutan (0.60) and Deepthi (0.44) for fruit yield per vine. The maximum sca effects was observed in the cross COHB-1 × Deepthi (1.64) followed by COHB-32 × Arka Sumeet (1.12) and COHB-32 × Pusa Nutan (1.03)