Variability in sucrose content at grand growth phase in tissues of Saccharum officinarum Saccharum spontaneuminter-specific hybrid progeny

Abstract

The variability for sucrose content in existing commercial sugarcane germplasm is not large and hence crosses were made between two Saccharum officinarumclones, ‘Gungera’ (cross I) and ‘Keong’ (cross II) with high sucrose content and a clone of Saccharum spontaneum ‘SES 603’ with low sucrose content. A high sucrose commercial var. CoS 8436 was also crossed with a low sucrose var. Co 1148 (cross III). Among the three crosses, only cross I germinated to give healthy twenty nine inter-specific hybrids. Inter-specific hybrids selected from cross I were graded into very high, high, low, and very low sucrose classes on the basis of morphological characters. Also anthrone method of sucrose estimation from internode, Brix value and quality analysis were done on whole sugarcane stem at different growth stages. Rate of photosynthesis, transpiration and stomatal conductance were analyzed using infrared gas analyzer and was found to be high for high sucrose hybrids. Rate of assimilate translocation of sucrose was also estimated with radio-labelled 14C and was found to be highest in the midribs. On this basis, molecular markers for high and low sucrose content ISH-1, ISH-5, ISH-17 and ISH-23 were identified as very high and ISH-10, ISH-11, ISH-12 and ISH-25 as very low sucrose hybrids. Key words: Inter-specific hybrids, sucrose content, sugarcane, TVD leaf.