Genotypic differences in lodging and Mechanical strength in stalks and Peduncles of Pearl millet (Pennisetum glaucum (L.) R. Br.)

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Muuka, Ferdinand P
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Differences were found in lodging and mechanical strength tests among pearl millets, pearl millet x Napier grass (PMxNG) lines, test crosses and sorghum. In 1987 field lodging ranged from 0 to 98%. Test crosses with PMxNG lines lodged worse on average than the millets or sorghum, but they were superior to the millets and sorghum in mechanical stalk strengths tests crosses was due to peduncle breakage. Stalk and peduncle lodging were distinguished in 1988 and peduncle lodging was more critical than stalk lodging. The PMxNG test crosses were superior to the millet and sorghum in rind thickness of basal stalk internodes, which in all genotypes was correlated with stalk crushing strength (0.59* to 0.97**) and stalk breaking strength (0.70** to 0.98***). Sorghum was generally superior in all traits except stalk crushing strength, yield, tillering and peduncle length. Unlike millet increased peduncle length in sorghum had no effect on either stalk or peduncle lodging. Rind thickness and diameter were important in imparting strength to stalks and peduncles. The range of correlations found between traits were 0.49* to 0.84* for rind thickness diameter of peduncle; 0.74** to 0.86*** for peduncle with stalk diameters; and 0.69** to 0.90* for diameter with length of peduncle. Inconsistencies existed between field lodging and mechanical strength tests. Strong correlations were found (0.77** to 0.96**) between crushing strength and breaking strength and but correlations between the stalk and peduncle tests were inconsistent. Although there was heterosis for increased stalk and peduncle strength in test crosses, increased height, tillering and yield often gave more lodging. Generally, seed parent 68B (or 68A) per se or in test crosses proved superior to 23DBE (or 23DAE) in peduncle lodging. The best average combiners were lines 86-59110-9 for stalk diameter and rind thickness and 88134 for peduncle rind thickness.