Prevention of false smut (Ustilaginoidea virens) on rice hybrids and pure‐line cultivars by manipulating planting date

Abstract

AbstractFalse smut of rice is an emerging disease and a potential threat to hybrids and inbred rice cultivars grown in Asian countries. The aim of the study was to avoidance of false smut incidence by manipulating the planting date in rice. The genotypes including five rice hybrids, namely, KRH 2, US 312, DRRH 3, PHB 71, PA 6644 and three pure‐line cultivars, namely, BPT 5204, PR 116 and HKR 47 were evaluated in different planting dates (PD1: June 25, PD2: July 5, PD3: July 15). All the tested genotypes flowered during 100–110 days, except BPT 5204, which took 115 days to flower. False smut was quantified on rice genotypes using different disease variables such as infected panicle/plant, total false smut ball/plant and disease score. Disease variables were significantly and positively correlated to each other. The significant interaction between the genotype and planting date was observed. The early planting date (June 25) showed higher incidence than late planting (July 15). Overall mean of disease variables was higher in hybrids than pure‐line cultivars. Weather factors such as rainfall, rainy days and high relative humidity during the flowering period were favourable for disease development. The manipulation in the planting date can be utilized as a potential non‐monetary cultural approach for minimizing the incidence of false smut in rice. Cultivar HKR 47 with lower disease variables in different planting date can be used in diseases resistance breeding program.