Flowering behaviour, pollen fertility and relationship of flowering with cane yield and sucrose accumulation among sugarcane germplasm accessions in a savanna ecology of Nigeria

Information on flowering behaviour of parental clones in sugarcane provides the breeder with the opportunity to design an efficient hybridization programme aimed at the development of productive varieties that will replace existing cultivars. Therefore, assessment of flowering behaviour and its relationship with cane yield and sucrose accumulation in the juice was investigated in thirty-six sugarcane genotypes comprising of thirty exotic accessions from Barbados, West Indies and six (6) standard varieties at the Unilorin Sugar Research Institute farm for two cropping cycles. The objective was to identify clones that will be suitable for hybridization aimed at development of high yielding sugarcane varieties for cultivation on the Nigerian sugar estates. Our results showed that the accessions differed significantly for most of the characters studied with many of the introductions showing superiority for cane yield and sucrose content compared to the existing cultivars. Notably among these are accessions B 76251, B 80689, KNB 9211, D 8415 and B 85877 which yielded between 75 and 81tons/ha-1. The genotypes formed three distinct groups based on period of flowering (early, mid and late flowering respectively). Sexual classification based on pollen fertility revealed that only four (4) of the 20 flowering sugarcane genotypes (ILS-002, B 78679, B 85877 and KNB 9211) were male sterile and so could be used as females in our hybridization programme. An inverse relationship was observed between cane yield and field brix suggesting that different genes code for each trait. The trend in sucrose accumulation showed that non-flowering genotypes had higher brix content than the flowering types throughout the sampling period while the late flowering types also had higher brix content compared to early or mid-flowering types. Few of the flowering types (for example, KNB9211, B80689 and D8415), also combined high cane yield with acceptable sucrose level and could be utilized in hybridization scheme to evolve superior progenies that would eventually replace the currently low yielding varieties on the sugar estates.