Additive Main Effects and Multiplicative Interaction for Seed Cotton Yield Performance and stability in Bt Cotton Hybrids (MON531 and MON15985)

A study was conducted to understand the stability of seed cotton yield of 105 Bt cotton hybrids (BGI and BGII) using Additive Main effects and Multiplicative Interactions (AMMI) analysis across three diverse locations in India during rainy season 2018. This study holds importance as the hybrids were resistant to Helicoverpa bollworms due to Bt events (MON531 and MON15985) in them which were expected to nullify variation arising out of differential bollworm pressure in different location, unlike in non Bt hybrids where this variation also played role in the stability of the hybrids. The main effect differences among hybrids (41.23 %), environments (39.56 %) and the interaction effects (19.21%) were highly significant of the total variance of seed cotton yield indicating a large difference between the testing location causing different hybrids to perform differently across the testing environments. The first two principal components axes (IPCA I and IPCA II) were highly significant and contributed 52.12 % and 47.88% of total interaction respectively. The distance from the origin and the placement of locations in different quadrants of biplot reflected that the locations were substantially discriminatory as Aurangabad and Dharwad, which were high yielding and Raichur was low yielding. Results showed that hybrids IAHH-8096 BGII, IAHH-8103 BGI, IAHH-8061 BGII and IAHH-8007 BGII were having lowest interaction and stable across the location, whereas hybrids IAHH-8080 BGI, IAHH-8084 BGI, IAHH-8004 BGII and IAHH-8105 BGI were having more interaction and unstable genotypes. Large frequency of hybrids (57) were stable with IPCA scores nearing zero and low ASV values which is attributed resistance to bollworm due to Bt events.