USING SELECTION INDEX FOR IMPROVING SOME ECONOMIC TRAITS IN COTTON (G. barbadense L.) | ||||
| Egyptian Journal of Plant Breeding | ||||
| Article 2, Volume 24, Issue 1, March 2020, Page 21-40 PDF (802.92 K) | ||||
| Document Type: Original research | ||||
| DOI: 10.12816/ejpb.2020.199304 | ||||
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| Abstract | ||||
| The present study was conducted during three growing seasons of 2016, 2017 and 2018 at Sakha Agricultural Research Station. Three generations F2, F3 and F4 of the intra specific cotton (Gosssypium barbadense L.) cross Giza 86 x Pima S6 were used to study the selection index and to compare it with direct and indirect selections to detect superior families, in addition to estimate correlated response to the selection also to predict and realize genetic advances from different selection procedures. A comparison of mean performance for different traits among the three generations F2, F3 and F4 revealed increase in mean values for all traits with advanced generation's fromF2 to F4, except micronaire reading (desirable values). PCV and GCV were generally larger in magnitude for all studied traits in F2 generation as compared with advanced generations F3 and F4. High heritability values over 50% were recorded for most studied traits over generations, indicating high magnitude of genetic variability and gave possible success in selection in early generations. Significant desirable correlations between boll weight and each of seeds /boll, seed index and lint /seed were existed over the three generations. Predicted and realized genetic advances from different selection procedures revealed that ten out of eleven selection indices were more efficient than direct selection for improvement of lint yield in F2 population. The highest predicted genetic gain from F2 generation for lint yield/plant was observed when selecting for lint yield/plant with bolls/plant (IW1) followed by selecting for lint yield/plant with lint/seed also lint/plant with boll/plant and selection index in involving lint yield/plant with seeds/bolls. The highest actual genetic gains from F3 generation for lint yield/plant occurred when selecting directly for lint yield/plant. However the indices IW23 (Selection index involving lint yield/plant, seeds/boll and lint/seed) followed by IW123 and IW3 (Selection index involving lint yield/plant, bolls/plant, seeds/boll and lint/seed and selection index involving lint yield/plant and lint/seed) were superior to all selection procedures in amount of actual gain and most indices showed high discrepancy between predicted and actual genetic gain as lint yield/plant. Maximum predicted and actual genetic advance from F3 and F4 generation for lint yield/plant were achieved when selecting for lint yield/plant and bolls/plant followed by selection indices containing lint yield/plant, boll/plant, seed/boll and lint/seed as well as selecting for bolls/plant and lint/seed. Direct selection for lint yield/plant and selection index involving lint yield/plant, seeds/boll and lint/seed gave high values of realized advance for bolls/plant, seeds/boll and lint/seed (selected traits) and most yield traits.All selected families exceeded better parent and point start of F2 means, however some of these families surpassed F3 families mean for yield traits as well as fiber quality traits. The breeder may utilize such selected families in breeding programs aiming to improve yield and quality. | ||||
| Keywords | ||||
| Genetic advance; Selection procedures; Cotton; Selection index | ||||
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