Screening of rice varieties for direct seeding method

Direct seeding method of rice planting offers several advantages. However, all rice cultivars are not suitable for this practice. In this report forty-three high yield rice varieties and an anoxia/hypoxia tolerant control land race were studied to verify their suitability to establish seedling under anaerobic conditions. The study was conducted in controlled field conditions. The percentage of seedling establishment, first leaf, plant height, root length, leaf number and seeding depth parameters were observed. The varieties were grouped into six different clusters following cluster and discriminant function analysis (DFA). As hierarchical clustering was done in the analysis, the genotypes clustered mainly on the basis of higher value of discriminating variables contributing to the first two principal components. The clusters 3, 5 and 1 located at the positive side of the Y-ordinate represented function 1. The best option from the selected cluster 3 was variety number 6 (BR6) showing the highest seedling establishment percentage (85%) and longest first leaf (1.97) and seedling height (2.86), seeding depth 0.5, root length 1.65 at low land condition. The other varieties from the same clusters were variety 9, 15 and 17. There was a negative relationship (0.756) between seeding depth and seedling establishment. The surviving seedlings showed a tendency to push them towards the soil surface, which might be a morphological response for getting oxygen through their coleoptile tip. The screening revealed that BR6 is the best variety for direct seeding in lowland conditions.