Single defective character improvement, stepwise multiple regression, broadsense heritability, genetic variance of asexually propagated plant, isoenzyme, Succharum sp. hybrid.
Thirteen callus derivatives from the sugarcane (Saccharum sp. hybrid) varieties 'F156' and 'F164 were studied to investigate the potential of tissue culture methods to generate superior germplasm for plant breeding in a field trail conducted at a single location. Comparisons between callus derivatives and donors were made for 9 characters, viz. cane yield, sugar yield, stalk number, length, diameter, volume, density, weight/stalk, and percent fiber. Statistical analyses were run, which involved stepwise multiple regression, broad-sense heritability (H), genetic advance (AG). Esterase zymogram of superior callus derivatives was examined. 70-6132 was 32,34 and 6% higher than its donor (F164) in cane yield, sugar yield and stalk number, respectively. The differences between them for the first two characters reached the 5% probability level. 70-6132 was also higher for these 3 characters than F160, the No. 1 commercial variety, by 20, 16 and S%, respectively. 70-6136 ranked next only to 7&6132. Its grand means for these 3 characters outdid the parental (F164) means by 21, 24 and 3/o, respectively. 7&6069 was significantly higher in stalk diameter and volume than most of the callus derivatives but not higher than its donor (F156). The performances of other derivatives were either similar or inferior to both their donors and F160. Stalk number, stalk length and weight/stalk accounted for 43,29 and 18% of the variation of cane yield, respectively. H values for the 7 characters (stalk density and percent fiber were not included) ranged from 31 (stalk length) to 66% (stalk volume). AG/X x 100 for the 7 characters ranged from 3.3 (stalk length) to 18.6% (sugar yield). 7M132 had two bands missing, 7tX-6069 had two bands more whereas those of 70-6136 showed no visible change, in esterase zymogram as compared with the donors. Due to the improved yield and the genetic changes revealed by the isoenzyme patterns in callus derived lines, tissue culture methods can be used to create superior varieties for agricultural use.