Improved method for increasing the efficacy of hybridization in soybean [Glycine max (L.) Merill]

Abstract

In general, hybridization is difficult in pulses due to cleistogamous flower. Among pulses, soybean has a very small flower with diadelphous stamens surrounding stigma, that necessiate extreme care during emasculation. The cross pod set depends in soybean to a larger extent on environmental conditions and also on the personal skill. Generally emasculation is carried out one day before the pollination resulting in the exposure of stigma to unfavourable environmental conditions. The low humidity and high temperature under tropical and subtropical conditions lead to drying of small stigma, which is the chief cause of poor crossing success. In order to overcome drying of stigma, Kolot [1] suggested emasculating the flower in early morning (5.00 to 8.00 am) and crossing on the same day. Different methods such as crossing without emasculation using a dominant marker [2], use of optical microscope under artificial climate chamber [3] and in field conditions [4], grease proof paper with isolotar [5], pollen storage and crossing in the evening hours [6] were successful under temperate conditions. However such methods are tedious, cumbersome and expensive under tropical and sub tropical conditions. Hence the present investigation was undertaken to develop a simple technique to achieve higher cross pod set under Indian conditions in soybean.