Studies on yield, root characters related to drought tolerance and their association in upland rice genotypes

Abstract

Plant selections with desirable root characters have been a major objective in breeding drought resistant variety of rice. Present study was therefore conducted to study the performance of rice varieties for yield, yield contributing characters, root characters and their association with drought tolerance. Drought resistant entries had recorded higher root thickness, root volume and deep root system than the susceptible genotypes. Correlation studies revealed that, all the characters showed positive and significant correlation with single plant yield. Drought score on the other hand exhibited significant negative correlation with yield. Spikelet fertility positively correlated with 1000 grain weight and yield but negatively correlated with drought score. Root depth was found positively correlated with root volume, root thickness, fresh weight of shoot and root and dry weight of shoot and root and exhibited significant negative correlation with drought score. This means that deep rooted varieties tend to be drought tolerant and have thick roots. Strong association between drought score and root thickness suggested that this character to be an important trait in identifying varieties for use in upland rice improvement for drought tolerance. Hence the characters to be given importance in selection are panicle/m2, spikelet fertility and 1000 grain weight as they exhibited highly positive correlation with grain yield and also a positive inter-correlation among themselves. Selection based on root thickness and root depth is highly suitable for identifying varieties for use in upland rice improvement for drought tolerance.

Keywords

• rice
• drought tolerance
• correlation studies
• root characters
• yield