Enhancing grain yield potentials in rice by increasing the number of high density grains
1986
Venkateswarlu, B. | Vergara, B.S. | Parao, F.T. | Visperas, R.M. (International Rice Research Inst., Los Banos, Laguna (Philippines). Plant Physiology Dept.)
Rice yield potential has reached a plateau. Several approaches have been tried to further increase grain yield potential but so far none has been successful. Experiments indicate that cultivars have different degrees of grain filling (grain density). Grains are graded by the specific gravity method. Weight of single grains can vary greatly. High density or quality grains have greater kernel volume and weight and higher head rice yield. Varietal differences exist in the number of quality grains. Potential yield is based on the average weight of the single grain. This should be based on the weight of the high density grain. This suggests that increasing the proportion of high dens1186ity grains would enhance the potential yield. An estimated 30% increase in grain yield is possible by increasing the number of high density grains. The proportion of high density grains to total yield decreased with an increase in N level from 0 to 250 kg N/ha. Of the five crosses assessed, four showed F1 progenies with more density grains than the better parents indicating that the character is heritable and heterotic. High density grain index, which is a ratio of the proportion of high density grain to the total number of spikelets produced, can serve as an effective tool for developing high yield potential in pl
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