Study On The Drought Tolerance And Yield Potential In Paddy And Upland Rice

In the current research, upland varieties, and indica and japonica paddy rice varieties, hybrid rice combinations and double haploid lines (upland rice X paddy rice) were used and planted under three irrigation ways, i.e. conventional (submergence), alterantive and rain-feeded irrigations, to study the performace of their agronomic traits. The main results are as follows:1, There was no obvious difference in grain yield between submergence and rainfed irrigations for upland rice. On the whole the yield of upland rice was lower than paddy rice. Li 148 Nuo, a variety derived from cross of paddy and upland rice vareities, expressed the highest yield and drought tolerance. In terms of yield components, Li 148 Nuo is characterized by stronger tillering ability and more productive tillers, higher and more stable grain-setting percentage and ratio of grain/straw. It may be assumed that the genotypes carried the sd-1 gene.2, The indica rice generally showed higher yield potential and drought tolerance, in comparison with japonica rice. The genotypes with high drought tolerance, such as Ke 22 Xuan were identified from paddy rice gerplasm, which had the same tolerance as upland rice did. Compaerd with conventional varieties, hybrid rice had better yield and higher drought tolerance, indicating heterosis in stress tolerance except in yield potenial. Under the condition of rainfed paddy field, it could be possible to identify the genotypes with higher drought tolerance.3, A DH (double haploid) population lines were developed through anther culture of F1 between a upland rice (IRAT359) and with a paddy rice (T461), and 23 DH lines were choosed randomly for using in studying the perforamce of agronomic traits under thee irrigation ways. It was found that the yield of most lines ranged between the two parents, while a few line had lower yield. In addition, there were four lines, i.e. W29, W31, W34 and W29, which showed the high and stable yields in all irrigation methods, being higher than upland rice IRAT359.Based on analysis of the present results and with the objective of carring out water-saving rice production in southern China, the rice variety being used in upland and paddy fields should be emphasized. Thus the folloing issues should be considered: (a) to improve the yield potential of upland rice through enhancing tillering ability;(b) to focuse on paddy rice in further identification of drough tolerant genotypes;and (c) to make hybrid rice breeding as a platform in improvement of dought tolerance in rice.