Survival of Genotypes in a Mixture of Fourteen Sorghum Varieties

Competition among divergent genotypes in sorghum was studied in three sets of experiments in the 1961 kharif season at New Delhi. The number of plants surviving at the end of one season of natural selection was determined in each variety and per cent. of survival was calculated. Tall growing types were observed to have a higher survival rate presumably owing to their better adaptation and smothering effect on the dwarfs. The range of survival varied from 1.5 to 93.0 per cent. The lowest rates of survival, namely, 1.5 per cent. to 12.0 per cent. were observed in the dwarf varieties I.S. 106 and I.S. 408 respectively. The highest survival values, 90.5 per cent. and 93.0 per cent., were obtained for I.S. 1056 and I.S. 1060, respectively. The role of natural selection favouring tall types was indicated.

A study of the effect of intergenotypic competition in mixtures for six plant and ear characters indicated that plant height, length and breadth of ear and number of panicle branches were significantly reduced while number of internodes and weight of 100 grains were not affected.