Studies on alloplasmic and euplasmic heterosis in Brassica juncea L.
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Date
2017-11
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
The present investigation was aimed to estimate heterosis and combining ability in Ogu alloplasmic hybrids as well as euplasmic hybrids, determine specific cyto-nuclear interactions and influence of ogu cytoplasm on hybrid performance. Experimental material consisted of 30 euplasmic hybrids generated by crossing 10 lines viz. PRL-2008-5, PBR-357, Maya, PRKS-28, Rohini, Sej-2, Vaibhav, EJ-22, PYR-2009-5 and PYR-2009-13 and three testers viz. IC-414317, IC-414322 and PR-2006- 14. Besides, same set of lines converted into ogu CMS background was used to develop 30 alloplasmic hybrids by crossing with three restorers (same set of testers carrying restorer gene). The parents, euplasmic and alloplasmic hybrids were evaluated in Compact Family Block Design with three replications during rabi 2016-17 at N.E.B.C.R.C., G.B. Pant University of Agriculture and Technology, Pantnagar. The data recorded on 13 characters was subjected to combining ability analysis (Kempthorne 1957), heterosis over mid parent as well as better parent (Hayes et al., 1955) and difference of mean values of two set of F1’s to determine extent of biological penalty. ANOVA revealed that mean squares due to families were significant for all characters while within family variance were found non-significant only for siliqua density. ANOVA for line × tester performed separately for both sets showed that treatment variance was significant for all characters in both the sets. Further partitioning of total variance into parents, crosses and parents vs crosses revealed that variance due to parents was significant for all characters except 50 % flowering and days to maturity in euplasmic set; and number of primary branches in alloplasmic set. Partitioning of variances due to crosses into lines, testers and line × tester in both sets showed significance mean squares for most of the characters. Mean squares due to testers were significant for number of primary branches, number of secondary branches, yield per plant and 1000 seed weight in alloplasmic set and for number of secondary branches and yield per plant in euplasmic set. For lines in euplasmic set, characters like plant height, length of main raceme, siliqua length and yield per plant showed significant differences while in alloplasmic set only yield per plant exhibited significant mean square. Variances due to line × tester interactions were significant for all characters in alloplasmic as well as in euplasmic set except siliqua length and number of seeds/siliqua in the latter. Based on desirable GCA effects, PBR-357, PYR-2009-5 and EJ-22 were identified as promising lines in euplasmic set while PBR-357A and PRL-2008-5A were high GCA lines in alloplasmic set for seed yield per plant. Among testers, IC-414317 and it’s A-line were found to be good general combiner in euplasmic and alloplasmic sets. The lines PBR-357, Maya, PR-20 in euplasmic and PBR-357A, PR-20A and RohiniA in alloplasmic set were identified as promising donors for oil content. Among testers IC-414322 was found to be good donor for oil content in both sets. Of these PBR-357, was found to have high GCA for seed yield per plant as well as oil content converged with key components. In euplasmic set, two crosses PBR-357 × PR-2006-14 & PR-20 × PR-2006-14 showed significant SCA for seed yield per plant and oil content. On the same analogy, three crosses MayaA × IC-414317, RohiniA × IC-414317 and EJ-22A × IC-414322 in alloplasmic set manifested significant SCA effects for these end products in desirable direction. The heterosis of high magnitude was manifested by large number of crosses for seed yield per plant in euplasmic as well as alloplasmic sets. Maya × IC-414317 manifested highest heterosis followed by Maya × IC-414322 and PBR-357 × PR-2006-14 in both of the sets while PBR-357 × IC-414322 and PBR-357 × PR-2006-14 for oil content were two promising combinations in both sets, respectively. The results revealed considerable amount of biological penalty which varied with cross combination and the characters. All crosses exhibited biological penalty for one or more characters under study. However, five alloplasmic cross combinations viz. PBR-357A × IC414317, PBR-357A × IC-414322, EJ-22A × IC-414322, PYR-2009-5A × IC414317 and PYR-2009-13A × PR-2006-14 performed better than corresponding euplasmic cross combinations for seed yield per plant indicating a positive cytoplasmic effect i.e. effect of cytoplasm was negated by restorer. Such combinations appear promising for commercial hybrid crop production. In the present study, influence of cyto-nuclear interaction was studied by comparing the estimates of GCA, SCA and manifestation of heterosis in euplasmic vis-à-vis in alloplasmic set of crosses. Comparison of GCA, SCA and heterosis estimates for different characters showed that it may or may not be affected by the cyto-nuclear interactions. There was complete change in the GCA status (Good to Poor or Poor to Good) of different lines for 3 or more characters. For example, PBR-357 exhibited changed GCA status for 9 characters, Maya for five characters; and PR-20 for only three characters i.e. siliquae on main raceme, number of secondary branches and siliqua length. GCA status nine lines were consistent in euplasmic as well as in alloplasmic sets for seed yield and six lines for plant height. Similarly visible influence of cyto-nuclear interaction was observed on SCA and heterosis in large number of crosses for different characters.
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