Evaluation of Drought Tolerance Potential of Elite Genotypes and Progenies of Sugarcane (Saccharum sp. hybrids)

Abstract

In order to identify drought tolerant genotypes and study the pattern of segregation for drought, 28 elite sugarcane hybrids and 165 progenies from a proven commercial cross (Co 740 × Co 775) were evaluated for sugar yield attributes and biochemical parameters under normal and drought conditions. In the genotypes, higher reduction in drought in relation to the normal condition were observed for internode length (45.76 %), single cane weight (25.5 %), NMC (22.8 %), cane length (20.10 %) and sucrose content (18.73 %), while cane diameter (2.92 %), internode number (3.58 %) and Brix (−6.99 %) showed marginal variation. Similar reduction in cane height (35.05 %) and internode length (25.13 %) in the progenies indicated that cane length was more adversely affected by drought and the reduction was through shortening of internodes than reduction in internode number. These two easily scorable parameters in field and showing significant positive correlation under normal and drought conditions could serve as reliable characters in drought screening. Nitrate reductase activity showed reduction in the genotypes (39.11 %) and progenies (44.95 %), while proline accumulation and activities of superoxide dismutase and peroxidase almost doubled in the genotypes and progenies. The tolerant genotypes viz. Co 740, ISH 100, NS 83/247, Co 85019, Co 997 and Co 99008 could be utilized in crop improvement, while Co 419, Co 8021, Co 775 and Co 8368 were susceptible. Higher proportion of drought tolerant genotypes reflected the genetic nature of sugarcane hybrids with genome contribution from the drought tolerant species S. spontaneum.. The population of 165 progenies was categorized into five classes of varying levels of tolerance that followed a normal distribution and hence its value as an immortal mapping population for genetical and molecular studies on drought tolerance.