1990 Volume 34 Issue 1 Pages 20-26
In recent years, so-called grain sterility has become a serious problem for rice production in Sri Lanka. Surveys and investigations aimed at clarifying the causes of this phenomenon were carried out using panicles affected with so-called sterility that were collected from experimental and farmers' paddy fields in three representative climatic zones during the 1985 Yala and 1985-86 Maha cropping seasons. Percentage fertility of each sample affected with so-called sterility distributed within a normal range in both Yala and Maha seasons, except for 3 samples which showed low percentage fertilities. While pollination and fertilization were considered to be normal, the percentage of whole grains was significantly low in almost all the samples.
The major causes of unfilled grains were ascribed to damage to grain development by the Rice Bug (Leptocorisa oratorius Fabricius) and Bacterial Grain Rot of Rice (Pseudomonas glumae Kurita & Tabei) . More than 80% of grain damage occurred within 8 days after flowering.
