Pedigree analysis of sugarcane parental breeding pool used in evolving ‘Co’ varieties in India

The pedigree of the commercial sugarcane varieties (‘Co’ canes) evolved from Sugarcane Breeding Institute, Coimbatore, India during 1970–2009 was studied. A total of 1088 ‘Co’ canes with known pedigree were evolved, among them 934 were from bi-parental crosses. The decade wise usage of breeding stocks revealed that clones Co 86011 (during 2000–2009), Co 7201 (during 1990–1999), CoC 671 (during 1990–1999 and 1980–1989) and Co 775 (during 1970–1979) were the most successful parents in evolving ‘Co’ canes. Fifty nine breeding stocks produced > 5 ‘Co’ canes each, contributed nearly 80% gametes to the total ‘Co’ canes evolved during 1970–2009.The pedigree study revealed that most of them (54) have POJ 2878 in recent ancestry indicating that their genetic variability is from limited origin. The breeding clones Co 775, CoC 671, Co 7201, Co 6806, Co 1148, Co 419 and Co 740 were the most successful parental stocks for evolving higher number of ‘Co’ canes across the studied period 1970–2009. The inbreeding coefficient or the coefficient of parentage (CoP) ranged from 0.00 (B017, Co 617, Co 853, Co 281, Q 63, Co 88002 and IG-91-1100) to 0.55 (Co 1307) with the average value of 0.09. Thirty-five parental clones have lower CoP than the average and their gametic contributionis evident to nearly 50% of the ‘Co’ canes evolved during the studied period.This indicated that even though having originated from limited clones of basic species, the genetic base of more than half of the breeding stocks is broader. More basic species clones are to be incorporated into the breeding programme for keeping higher level of geneticdiversity in future sugarcane varieties.