Influence of drought stress on growth, yield and yield components of selected maize genotypes in coastal lowland Kenya

Abstract

The risk of drought is high in the coastal lowland Kenya because rainfall in the region is unpredictable in quantity and distribution. Despite the availability of improved maize varieties farmers still grow local coastal maize landraces (LCML). The research was to study LCML in an effort to understand why farmers in the region prefer to grow them in spite of released improved maize open pollinated varieties (OPVs) and hybrid. The objective was to screen for drought tolerance in 25 LCMLs and 5 improved checks. The genotypes were evaluated for tolerance to terminal water deficit before flowering. The design was randomized complete block design (RCBD) with split plot arrangement of treatments. The screening was carried out at Kenya Agricultural Research Institute (KARI) Kiboko, genotypes were grown in water stress and well watered regimes. The traits measured were leaf rolling (LR), leaf senescence (LS), anthesis to silking interval (ASI), ears per plant (EPP), and grain yield (GY). Drought stress reduced grain yield by 28% from 0.96 t ha-1 in well watered environments to 0.69 t ha-1, in the severe stress environment. Drought at flowering results in bareness. Ears per plant (EPP) were also reduced by 55% from 1.01 ears in the well watered environment to 0.45 ears in the severe stress environment. Water deficit significantly reduced growth, grain yield and yield components of the maize genotypes. In stressed maize the pollen begins to shed but silks emergence is delayed by 3 or 4 days. In fact pollination shedding may stop before all the silk have emerged and a blank ear will result. Local coastal maize landraces like entries: 3 (Mdzihana), 11 (Kanjerenjere), 16 (Mungindo) all from Kilifi County and entries: 9 (044454) and 17 (Gonjora) all from Lamu County of the coast region of Kenya are drought tolerant and can be used by the resource poor farmers to stabilize maize grain yield in the coastal lowland of Kenya, where recurrent drought threatens grain production. They can also serve as sources of drought tolerance for the developing and improvement of new drought tolerant maize genotypes. Key words: Assimilates, climate, irrigation, morphological, physiological, and tropical