R. K. Gumber

Genetics of flowering patterns in pigeonpea: further evidence for two gene control

F2 and backcross populations of eight crosses among seven parents of different growth habits were studied to determine the genetics of flowering patterns in pigeonpea. Our results confirmed the presence of two independent genes (Dt1-Dt2-) for flowering pattern in pigeonpea. The expression of Dt2 gene controlling semideterminate flowering pattern was completely suppressed in the presence of Dt1 gene controlling indeterminate flowering pattern. Both the genes in homozygous recessive form (dt1dt1dt2dt2) caused determinate flowering pattern.

Impact of Harvest-aid Defoliants on Yield of American Cotton and Their Monetary Evaluation

Field experiments were conducted during Kharif 2012 and 2013 to determine the effect of two harvest-aid defoliants i.e Dropp ultra® and Ethrel, their application rates and time of application on three American cotton cultivars. Pooled data revealed significantly higher seed cotton yield for Bt hybrids MRC7361BGII (3055.2kg/ha) and MRC7017BGII (2913.0 kg/ha) as compared to non Bt variety F1861 (2346.0 kg/ha). Among tested defoliants, Dropp ultra® @200ml/ha resulted in better SCY, lint and seed yield. This yield enhancement in case of Dropp ultra® @ 200 ml/ha further lead to significantly better net returns (? 85373/ha) and B: C ratio (2.31) over other treatments. Application of defoliants at 150DAS resulted in significantly improved net returns (? 79288/ha) as compared to earlier application (? 73632/ha) at 140 DAS. Improved water productivity and fertilizer use efficiency coupled with better B: C ratio for Dropp ultra® @ 200 ml/ha at 150 DAS clearly indicated its superiority among all treatments. Therefore Bt hybrids seems to be superior over the non Bt varieties and application of ethrel@2000ppm or dropp ultra® @ 200 ml/ha at 150 DAS should be adopted as useful production practice for enhancing cotton yield under semi-arid conditions of north-western India.

Study of genotype x environment interactions and stability among diverse Gossypium arboreum L. genotypes for yield and related traits under North Western Plains

The present investigation was undertaken with an objective to determine the effect of genotype × environment (GE) interactions and stability on Gossypium arboreum genotypes belonging to different part of country for seed cotton yield and related traits. Seventeen Asiatic cotton genotypes were evaluated in randomized block design at Ludhiana, for two years (2010 and 2011) and at Faridkot for one year (2010). The significant genotypes, environments, genotype × environment interactions were observed for all traits. Stability parameters revealed LD694 and LD902 were most stable and significantly outperforming for most of the traits except halo length where DLsa1001 was ahead. Genotypes developed at Punjab were found to be more stable for most of the traits whereas genotypes from other centers can be used as germplasm for pre-breeding programmes.