GENETIC STUDIES FOR VARIOUS BIOLOGICAL TRAITS IN Chrysoperla carnea STEPHENS (Neuroptera : Chrysopidae)
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Date
1996
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AAU, Anand
Abstract
The present investigation was carried out to study the genetic variability in the six parental populations of ChryBoperla carnea Stephens originally collected from six different geographical regions of India, and the magnitude of heterosis, combining ability, gene actions and components of genetic variances following Griffing (1956a, 1956b) and Hayman (1954a, 1954b, 1958) approaches in diallel crosses involving above six parental populations at Biological Control Laboratory of Gujarat Agricultural University, Anand Campus during 1993-1995. The results on genetic variability revealed the presence of wide genetic variability for most of the biological traits in the parental populations of C. carnea studied. High heritability coupled with high genetic advance observed for post-oviposition period, fecundity and oviposition period suggested that phenotypic selection would be very effective for the improvement of these traits. Mean squares due to parents, hybrids and parents Vs. hybrids revealed significant differences for most of the traits under study. Based on the mean performance for various bioLogicaL traits, Anand population (A) proved to be the best followed by Aurangabad (AU), Jalgaon (J) and Hisar (H) populations Among crosses, AxS and AxAU proved to be the best crosses which involved Anand population (A) as one of the parent. The results on the magnitude of heteroeia supported the idea of exploitability of hybrid vigour in C. carnea for commercialiasation of the predator. The crosses viz., AxS, BxAU, AUxS, AUx J, BxJ, SxJ, SxH and JxH showed high magnitude of heterosis and heterobeltiosis for many of the important biological traits which can further be exploited in future breeding programme. In the present study, diallei assumptions were met for all the biological traits except feeding potential and pupation. Analysis of variance for combining ability revealed both additive and non-additive gene actions were responsible for the inheritance of majority of biological traits under study. However, the ratio of ogca2/osca2 suggested the preponderance of additive gene action for all the characters except male longevity, fecundity, feeding potential, pupation, pupal duration and larval tolerance to monocrotophos for which non-additive gene action was more pronounced. Among parents, Anand (A), Hisar (H) and Aurafigabad (AU) populations showed significant desirable gca effects while among the crosses, AxB, AxAU, AxS, BxJ, SxJ and JxH exhibited significant desirable sea effects for many of the biological traits. Components of variance analysis showed larger magnitude of dominance components and presence of over dominance for all the biological traits under study. Graphical analysis revealed considerable genetic variability and diversity, over dominance, asymetrical gene distribution and complementry type of epistatis for majority of the biological traits studied. The heritability estimates were low for majority of the biological traits except adult emergence and larval duration where moderate to high heritability estimates were observed. Overall study revealed the presence of great deal of genetic variability and diversity for majority of the biological traits studied. Since, diallel analysis following both Griffing and Hayman approaches revealed the importance of both additive and non-additive gene actions for the inheritance of majority of the biological traits under study, cyclic method of breeding/recurrent selection would profitably be employed for the improvement of these traits. High magnitude of heterosis and heterobeltiosis observed for many of the important biological traits studied also suggested the feasibility of utilizing hybrid vigour on commercial scale.
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AGRICULTURAL ENTOMOLOGY, AGRICULTURE, A STUDY