Our laboratories are interested in using recombinant DNA techniques to study the genetics of amino acid metabolism in soybeans. An especially useful technique used to study gene regulation is the in vitro synthesis of DNA com-plementary to mRNA; this cDNA can be used directly as a hybridization probe, or cloned and amplified in a suitable host. The protocol described here was developed for isolating total cellular poly{A)-containing RNA from soybean suspension culture cells of sufficient purity for use as a template for cDNA synthesis.

The varieties of a crop with their differential genetical makeup exhibit wide variation in regard to both growth habits and ultimate yield. The main-tenance of optimum plant population will not only provide ample scope for proper growth of a variety but will largely shape the ultimate yield, because the yield of a crop in general is a function of yield per plant and plant popu-lation per unit area. Experimental evidence is available to show that optimum plant populations per unit area for different soybean varieties are not the same (Singh et al., 1974; Narayana, 1976; Reddy and Singh, 1976; Deshmukh et al., 1977).

The genus Glycine as currently delimited is divided into two subgenera Glycine and Soja. The subgenus Soja includes the soybean, G. max, and its annual wild counterpart, G. soja. The subgenus Glycine comprises seven wild perennial species.

In India, soybean is generally sown during summer (June-October). However, due to tremendous variability in climatic conditions of the country, there is a scope for growing soybean in more than one season. The efficacy of yield improvement projects could be substantially enhanced by rapid genera-tion turnover.