No abstract

Studies have shown that that about 85% of maize farmers in Western Kenya plant local varieties with about 80% using own farm-saved seeds. The production system is characterized by late harvesting, heavy striga infestation, use of local varieties, and low-soil fertility. The objective of this study was to test an on-farm seed production system which would help improve yield and quality of farm saved seeds. The trials were set up in a factorial design fitted as random complete block design. There were 3 factors each at 2 levels: time of harvest, variety choice, and fertilizer application. Fertilizer application led to an 88% increase in yield, 54% increase in number of seeds per cob, and 14% increase in 100-seed weight. Fertilizer application also led to an increase in seed vigour and viability. Yield differences between the 2 varieties were not significant. The correlation between 100-seed weight and seed vigour was significant showing that heavy seeds were more vigourous. Nitrogen application was therefore recommended for increasing yields and for producing vigourous seeds but should be done with caution to avoid lodging as witnessed. This study also noted that farmers are rational and their decisions are usually based on strong economic considerations.

A survey conducted in Western Kenya revealed that about 80% of farmers used farm-saved maize (Zea mays L.) seeds. During the survey, late harvesting, heavy Striga infestation, use of local varieties, and low soil fertility were identified as some of the constraints that farmers faced in on-farm maize-seed production. On-station and on-farm trials were carried out in seven divisions of western Kenya with the objective of testing an on-farm maize-seed production system and improving quality of farm-saved seeds. The trials were set up in a factorial design fitted as randomized completeblock design (RCBD). There were three factors each at two levels: time of harvest, variety choice, and fertilizer application. Results indicated that seeds harvested at harvest maturity had significantly better vigor (p = .001) and viability (p = .05) than those harvested at physiological maturity. The local landraces had significantly better vigor than Kakamega Striga-Tolerant Population '94 (KSTP), but differences in viability were not significant. Fertilizer application led to a significant increase in both vigor and viability. Harvesting of seeds at harvest maturity and application of appropriate quantities of nitrogen were, therefore, recommended to 150 P. W. Wambugu et al. farmers as practices that led to an improved on-farm production system of maize.

Effective germplasm conservation through seed banking requires that the viability status of every accession in the seed bank be known. This is normally done by conducting a germination test but is, at times, constrained by the presence of seed dormancy in some of the species. While dormancy release protocols have been developed for a majority of species, the same are lacking for others. The objective of this study was to determine the dormancy releasing procedure of selected species in the family Amaranthaceae to develop a germination-testing protocol for them. In this study, the influence of chilling, incubation temperature, potassium nitrate (KNO 3 ), and dehusking was investigated for 10 wild species. The effect of temperature on seed germination of species in the family was found to be significant (p ≤ .05) with most species performing better at alternating temperatures of 35 • C/20 • C as compared with constant ones. The effect of dehusking was highly significant on seed germination with the removal of seed covering structures promoting germination in Gomphrena celosioides and Aerva lanata. Application of chilling or KNO 3 treatment as dormancy release mechanisms, while causing a positive effect in some species, reduced germination in others. Out of the 10 species that were investigated in the present study, 6 had their seed-testing protocols successfully developed.