Volume 5 Issue 1

Studies on heterosis and yield stability in improved mulberry hybrids under irrigated gangetic alluvial soils of West Bengal

Author(s): M. K. GHOSH, N. K. DAS, SHIV NATH, P. K. GHOSH, A. GHOSH AND A. K. BAJPAI
Abstract: Eight newly developed mulberry (Morus sp.) hybrids viz., C-2036, S-1908, C-2037, C-2038, C-2039, C-2040, C-2041 and C-2042 were evaluated against S-1635 as check variety for growth, yield, physio-biochemical and bioassay parameters under irrigated conditions and zonal schedule of package of practices for cultivation in the alluvial soils of Gangetic plains of West Bengal. Among the test hybrids, C- 2038 was recorded to have higher number of shoots per plant (10.93), total shoot length (1059.95 cm), unit leaf area (284.06 cm²), unit leaf weight (4.87 g), net photosynthetic rate (13.53 μ mol m2 s^-1), physiological water use efficiency (1.028), carboxylation efficiency (0.0442), chlorophyll content (2.53 mg g-1 fr wt), total soluble protein (31.44 mg g^-1 fr wt), total soluble sugar (37.41 mg g^-1 fr wt) and leaf yield (55.23 mt/ha/year) and better economic parameters of cocoon showing its superiority over check and other test hybrids. Heterosis was studied for leaf yield and its attributing characters in 8 hybrids developed. Significant positive heterosis ranging from 5.95 to 159.31% over better parent, 13.92 to 159.31% over mid parent and 1.50 to 27.79% over standard variety (S-1635) was observed among the crosses for leaf yield. The leaf yield performance of eight hybrids and one check was tested for 3 years through stability analysis for 5 crop seasons per year. Significant genotype × environment (G × E) interaction was observed. Variance for deviation from regression (Sdi 2) of hybrids S-1908 and C-2039 did not differ significantly from zero. The bi value of these two hybrids is also not significantly different from unity hence these may be considered to be stable ones. The hybrid C-2038 having bi not significantly different from unity (1.023) and moderate but significant Sdi 2 (0.35) emerged as a high yielder with high heterotic value for leaf yield. This hybrid has been recommended for national trial before field level exploitation and S-1908 and C-2039 may be considered as stable parents in future breeding programmes.

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