Effect of Dirty Panicle Disease on Rice Seed Vigor

Abstract

This experiment was conducted at Prachin Buri Rice Research Center during 1994-1996 to study effect of dirty panicle disease on seed germination and seed vigor, especially germination index of rice seed. One hundred and two samples were collected from seed multiplication field of Prachin Buri Rice Research Center and Huntra Rice Experiment Station, and farmer field in Prachin Buri and Nakhon Nayoke provinces. Based on symptoms on the hulled grain, samples were classified into 7 groups ; spot, small lesion, large lesion, partial blackening, mostly blackening, fully blackening and clean seed. The samples were then tested for germination and germination index. It was found in most of the samples that spotted seed had germination and germination index not different from clean seed, whereas those of fully blacken seed decreased significantly with the germination of less than 80% Other groups, i.e., small lesion, large lesion, partial blackening and mostly blackening also showed difference in germination and germination index, which varied among varieties. Germination percentage of clean seed, spotted, small lesion, large lesion, partial blackening, mostly blackening and fully blackening were 97, 9 4, 88, 87, 84, 82 and 77 with germination index of 25.7 , 24.2, 22.8, 22.5 , 21.9 , 20.9 and 18.4 respectively.