Yanal ahmad Alkuddsi , S.S.  Patil , S.M.  Manjula , B.C.  Patil , H.L.  Nadaf , B.S.  Nandihali

Agricultural Research Station, Dharwad Farm, University of Agricultural Sciences, Dharwad, Karnataka, India
Author    Correspondence author
International Journal of Molecular Ecology and Conservation, 2013, Vol. 3, No. 6   doi: 10.5376/ijmec.2013.03.0006
Received: 17 Jul., 2013    Accepted: 30 Jul., 2013    Published: 30 Dec., 2013

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Alkuddsi et al., 2013, Exploitation of Heterotic Pools of Hirsutum and Barbadense for Developing Potential Inter Specific Hybrids in Cotton, International Journal of Molecular Ecology and Conservation Vol.3, No.6, 34-55 (doi: 10.5376/ijmec.2013.03.0006)

The elite barbadense combiners namely DB 533 and DB 534 were indentified for creation and exploitation of recombinational variability for combining ability. In 2007- 2008 this cross was made and early segregating generations were raised during 2008- 2009 / 2009-2010, out of 171 F3 lines 53 were identified based on productivity and fiber quality and advanced to succeeding generations. In F4 generation 28 barbadense lines were utilized to assess recombinational variability for combining ability. These selected F4 lines were crossed with 4 hirsutum testers figuring in the heterotic box identified in this study. The derived F1 crosses (28 x 4) were compared with the bench mark crosses (two barbadense lines x 4 hirsutum testers) of the heterotic box, best Bt check hybrid (MRC 6918) and non Bt check (DCH 32). The derived F1 crosses revealed considerable variability for per se performance measured in terms of productivity and fiber quality traits. Many derived F1 crosses were found to be more productive than non Bt check DCH 32 (48 hybrids) and the Bt check MRC 6918 (35 hybrids). The potential crosses like DH 98-27 X (DB 533 x DB 534 F4 IPS 49), DH 98-27 X (DB 534 x DB 533 F4 IPS 22) and DH 98-27 X (DB 533 x DB 534 F4 IPS 52) recorded highest per se performance for seed cotton yield. These crosses also recorded high value for yield attributing characters like number of bolls per plant, mean boll weight, seed index and number of sympodia per plant. These potential crosses recorded highly significant heterosis over mid parent for seed cotton yield. Apart from showing high productivity the potential cross DH 98-27 X (DB 533 x DB 534 F4 IPS 49 showed higher value of photosynthetic rate, stomatal conductance and fiber quality parameters. This potential cross is example for blending of yield characters, physiological parameters and fiber quality. The set of 28 lines distinguished for the ability to combine with each tester. The efficiency of tester in distinguishing of these F4 lines was determined based on mean seed cotton yield of 28 crosses and co-efficient of variability. In derived F1 crosses, tester DH 98-27 (T1) revealed high mean and also higher co-efficient of variance as compared to the other three testers for seed cotton yield. Both DH 98-27 and DH 18-31 were found to be efficient testers on the basis of high mean and high co-efficient variance. Considering mean and co-efficient variance as parameters T1 was found to be more efficient in distinguishing the barbadense F4 lines for their combining ability for utilized to distinguish lines. A method of sub grouping the F4 lines against each tester was done. Based on this elite combiner F4 lines were identified against each tester. This approach helped in sub grouping the F4 lines against a pair of hirsutum testers and identifying lines for deriving sub populations against hirsutum testers. Both the lines DB 533 x DB 534 F4 IPS 49 and DB 534 x DB 533 F4 IPS 22 have combined very well with four hirsutum testers. This suggests that these two barbadense lines can recombined to initiate second phase of creating recombinational variability for combining ability. The segregating F4 lines obtained from this cross can be crossed to these four hirsutum testers and especially DH 18-31 and DH 98-27 because the mean of crosses with these testers (T1 and T4) was very high. The F4 lines which gave more potential crosses than bench mark crosses were identified as transgressive segregants for combining ability (positive). Among the population used in the combining ability study, DB 533 x DB 534 F4 IPS 49, DB 534 x DB 533 F4 IPS 22 and DB 533 x DB 534 F4 IPS 52 F4 lines combined very well with all the four testers and revealed transgressive positive segregation for combining ability. These parents reveal diversity with respect to the identity of dominant favourable alleles contained in them. We can expect segregation at more number of yield influencing dominant loci. As a result of this variability is released at more number of loci and thus recombinant lines having desirable blend of favourable alleles distributed between two parents are obtained. Such lines give rise to superior derived F1 crosses. Key word: Recombinational variability, Efficiency of tester, Transgressive segregation, Sub grouping the F4 lines

Recombinational variability; Efficiency of tester; Transgressive segregation; Sub grouping the F4 lines