Variability Trends for Brix Content in General Cross Combinations of Sugarcane (Saccharum spp. Complex)

The study was undertaken to determine the potential of general cross combinations in sugarcane, obtained by open pollinating the female parents, to generate variants for Brix (percent total soluble solids) content and frequency distribution pattern of variants, hence generated. Using Brix (an indicator of sucrose content) as selection criterion, 819 ratooned seedlings raised from five general cross combinations, comprising high sugared commercial varieties of North West zone as female parents viz., CoS 8436, Co1148, Co Pant 97222, Co 0238 and Co 0239, were investigated. The adjusted Brix values of test genotypes, evaluated in augmented incomplete block design, inferred the generation of highly variable population with significant differences in test genotypes. Further cross wise evaluation revealed that progeny means of three GC’s raised from female parents CoS 8436, Co1148, Co Pant 97222 were significantly higher than respective parental means, whereas, the progeny obtained from high sugared female parents Co 0238 and Co 0239 has significantly lower mean Brix value than parental means, thereby signifying that determining the combining ability of parents is important to generate elite segregants since some parental combinations may not be able to transfer their potential economic values (traits) to next generation. Highly significant negatively skewed leptokurtic distribution of the progeny for Brix content in GCs obtained Co Pant 97222 and Co1148 indicated that the tail on the left side of probability density function was longer than the right side and the bulk of the values (including the median) lie to the right of the mean. This indicated that Co Pant 97222 and Co 1148 are potential female parents to generate high frequency of elite seedlings for Brix. The evaluation of elite clones from each GC in the next clonal Stage (Settling I) led to a higher selection rate in Co Pant 97222 and Co 1148 as compared to other GCs. The study suggested the scope of general cross combinations, which are less laborious, cost effective and generally yield more fuzz, to generate elite segregants for qualitative traits like sucrose content in sugarcane. The influence of female parents on frequency distribution pattern of elite segregants has been discussed.