ECOLOGICAL EFFECTS ON THE FLOWERING PHENOLOGY OF CENCHRUS CILIARIS L. COLLECTIONS FROM THE ARID AND SEMIARID LANDS OF KENYA

Abstract

Flowering is critical in plant ecology. Through flowering, plants evolve into new plant species that are better adapted to environmental variations. Cenchrus ciliaris is an important forage grass in Kenya, which is drought tolerant but is increasingly becoming depleted in grazing areas requiring reseeding. To identify suitable germplasm for such initiatives, collections from varied ecologies were evaluated at Kiboko to assess any adaptive morphological traits, particularly flowering related, that they may have been acquired in their evolution. Significant variation in days to start flowering (DSF) and days to full flowering (DFF) were observed between sites of ecotype origin and among the ecotypes. Ecotypes collected from Kilifi flowered significantly earlier than those from Kiboko while one Magadi ecotype, MGD3, was late flowering despite being collected from an arid zone. DSF was negatively correlated (p≤.0.001) to percent fertile tillers and the number of inflorescence per plant. Inflorescence length was positively correlated (p≤0.05) to the number of spikelets per inflorescence but negatively correlated (p≤0.001) to the percent fertile tillers. There was a trade-off between plant size and period to flowering where early flowering ecotypes were smaller in size and vice versa. However, a unique ecotype that defied the trade-off, MGD1 from arid agro-ecological zone VI, with both early flowering and robust traits was identified. Findings from Magadi collections indicate that collections from special niches may notbe applied as wide area adaptations, especially with regard to drought tolerance. The early flowering trait of some of the ecotypes matched results from various studies involving a wide range of crops other than grasses. The findings of the study provide opportunities for further selection and breeding work.