THE RELATIONSHIP OF PLANT MORPHOLOGIC PARTS ABOVE THE FLAG LEAF NODE TO YIELD AND YIELD COMPONENTS IN WINTER WHEAT

The study was conducted on 25 entries in the Fifth International Winter Wheat Performance Nursery. The cultivars, originating from different countries, were grown at the Agronomy Research Station, Stillwater, Oklahoma, U.S.A. The analysis of variance of all characters under the study showed that cultivars were different (P=.01) for all the characters studied; therefore, the nursery was suitable for the purpose of this study with cultivars differing genetically for all tracts. There was no significant difference among the top six cultivars for yield (L.S.D. .05). Golden Valley (Zg 5994/64) produced the highest yield ranking 8th, 5th, and 18th respectively, for kernel weight, kernel/spike and tillers. Among the yield components, kernel weight was the most important and tiller number the least important in terms of their influence on grain yield. Most high yielding cultivars had high kernel weight. The lowyielding cultivars were mostly late, and their maturity was hastened by hot, dry wind. A highly significant positive correlation between yield and kernel weight and significant positive correlation between yield and peduncle length was obtained. Yield was highly negatively correlated to percent protein and days to heading. Yield was positively related to kernels per spike, flag leaf area, flag leaf width, and chaff weight, but none of these correlations were significant. A good balance of yield components with more emphasis on seed weight should be helpful in selecting for increased yield.