Evaluation of Improved Saccharum officinarum and improved S.spontaneum hybrid derivatives for yield and biomass traits

Abstract

Sugarcane is a commercial crop that is cultivated across the globe for its sucrose. It is now recognized as an important energy crop which effectively utilizes solar energy and converts into chemical energy for biofuel production. Sugarcane as a bio feedstock contributes 40 % towards biofuel production worldwide and classified as the most favourable crop in terms of energy input and output ratio. Energy cane and commercial cultivars are generally derived from interspecific hybridization between Saccharum officinarum and S. spontaneum. S. spontaneum has contributed important traits to cultivars such as adaptation to environmental stress, diseases resistance and ratooning ability and recently it has gained importance for the improvement of wide adaptability, energy generation from biomass and high fibre. The genetic base broadening programme in Sugarcane Breeding Institute, Coimbatore involved the utilization of improved germplasm of S.officinarum and S.spontaneumin breeding programmes to identify clones with multipurpose utility which resulted in new gene pool of diversity and identification of genetic stocks for red rot resistance, yield, fibre, biomass and good juice quality. Even though this base broadening programme was to introgress important yield and quality traits, it also formed a source of clones with high biomass production and high fibre %.In this study, progenies from twenty three biparental crosses involving commercial sugarcane clones, improved S.officinarum and improved S. spontaneum clones along with parents were evaluated for cane population, tillering ability, cane height, cane diameter, total sugars,pol % juice, CCS %, total biomass and fibre %.

Statistically significant differences and high genetic variation was observed among the families and clones. Coefficient of variation was high for the attributes and it ranged from 18.83 % for fibre % to 44.80 % for cane yield. The F1clones exhibited high vigour with high cane population, tall and erect canes. Intensity of flowering was also high in these clones. The highest yield of fresh weight and dry matter biomass was obtained in first generation of improved spontaneum hybrid derivatives. Among the traits studied, cane length ranged from 185 -285 cm , fibre % (13.92 -22.05%), total dry biomass(5.92 to .35.01 kg/row), number of millable canes ( 42-98.24), total sugars ( 16.45 - 23.15 %) ,pol % juice (12.18 - 21.49 % ) and juice purity ( 78.62 – 92.86%). Among the crosses studied, eleven crosses were promising with number of millable canes above 91 / row of 3ft length, cane length of 285 cm, and Brix % of 23.15 %. The highest yield of dry matter and total biomass and fibre % was observed in the cross PIO 88- 96 x IND 82-319. CoC 671 x PIS 38 , PIO 88-1715 x IND 82-319 recorded highest brix % and pol % juice.PIO 88-96 x IND 82-319 ,PIO 88-96 x IND 82-319,PIO 88-104 x IND 82-319 were promising for millable canes, cane length and single cane weight. Moderate to high (0.41 to 0.78) heritability and high genetic variances were observed for all the traits. Moderate heritability was observed for fibre % and highest for single cane weight and total dry biomass. Correlation studies indicated that number of millable canes was positively correlated with fibre %. Moderate correlation was observed for CCS % and cane yield.NMC had positive correlation with cane yield, fibre % and CCS t/ha. All the traits except cane length had positive correlation with fibre %. Cane length, cane diameter and stalk weight had positive correlation with total dry biomass. Correlation studies within families also indicated both positive and negative correlations among the traits. The positive correlations of the yield traits with fibre % and total dry biomass indicates that direct selection for cane length, cane diameter and single cane weight will improve fibre % and total dry biomass. The genetic variability for the biomass traits and fibre % observed in this study indicates that selection of high biomass energycane families and clones at early generation will be advantageous and basic information on selection indices for these biomass traits has to be worked out for effective identification of biomass potential clones in our breeding programmes. The spontaneum parents viz., PIS 54, IND 82-319, PIS 18, and PIS 93-24 utilized in this study combine red rot resistance, erectness, vigour, moderate quality and can be further exploited in advanced breeding programmes to identify high biomass types. Seventy three elite potential recombinants identified from this study were further classified into two groups’ viz., high fibre with moderate total sugars and moderate fibre with high total sugar clones which forms a new energy source for energy and ethanol production. These clones showed moderate flowering and warrants large scale evaluation in multilocations which will be useful in identifying high biomass, well adaptable energy canes for the future.