Estimates of genetic parameters and expected gains from selection of yield traits in sugarcane families
Crop Breeding and Applied Biotechnology
It is essential to have basic information on the genetic nature of variation of various metric traits in plantation crops for the proper planning of breeding strategies. The objective of this paper was to estimate the variability for five yield traits in sugarcane (Saccharum spp.) families. Eighteen controlled pollination families were evaluated in a randomized complete block trial having 16 plants per linear plot at Jaú Development and Research Station (DDD/APTA/SAA), in Jau city, Sao Paulo
... city, Sao Paulo State, Brazil. In the second year, families were assessed and harvested six months after the first ratoon, and evaluated for the following characters: stalk height, stalk diameter, average Brix, stalk number and stalk weight. The results showed highly significant (p<0.01) genetic differences among families for most traits. The genotypic variance component accounted for 4.27, 3.55, 15.87, 3.32 and 51.68% of the phenotypic variance for stalk height, stalk number, stalk diameter, stalk weight and average Brix, respectively. Heritabilities at individual plant level for the above traits were 56.57, 76.59, 67.40, 72.73 and 54.11%, respectively. Negative significant genotypic and phenotypic correlations were found between Brix and stalk height (r g = -0.78**, r p = -0.56**) and stalk diameter (r g = -0.81**, r p = -0.75**). Selecting the best two families out of 18 families would result in a genetic gain of 4.92% and 10.82% for stalk height and stalk diameter, respectively. The best two selected individual seedlings within each family would result in a genetic gain of 18.61% and 16.94% with a total gain of 23.57 % and 27.76 % for these two traits, respectively.