Impact of adoption of drought-tolerant maize varieties on total maize production in south Eastern Zimbabwe

Drought is a huge limiting factor in maize production, mainly in the rain-fed agriculture of sub-Saharan Africa. In response to this threat, drought-tolerant (DT) maize varieties have been developed with an aim to ensure maize production under mild drought conditions. We conducted a study to assess the impact of smallholder farmers’ adoption of DT maize varieties on total maize production. Data for the study came from a survey of 200 randomly sampled households in two districts of Chiredzi and Chipinge in southeastern Zimbabwe. The study found that 93% of the households were growing improved maize varieties and that 30% of the sampled households were growing DT maize varieties. Total maize yield was 436.5 kg/ha for a household that did not grow DT maize varieties and 680.5 kg/ha for households that grew DT maize varieties. We control for the endogeneity of the DT adoption variable, by using the control function approach to estimate total maize production in a Cobb–Douglas model. The results show that households that grew DT maize varieties had 617 kg/ha more maize than households that did not grow the DT maize varieties. Given that almost all farmers buy their seeds in the market, a change in varieties to DT maize seeds gives an extra income of US$240/ha or more than nine months of food at no additional cost. This has huge implications in curbing food insecurity and simultaneously saving huge amounts of resources at the household and national levels, which are used to buy extra food during the lean season

GGE biplot analysisof genotypes by environment interaction on sorghum bicolor L. (Moench) in Zimbabwe

The genotype by environment interaction (GEI) reduces the success of genotype selection and recommendations by breeders, thus slowing down the progress of plant breeding. The understanding of genotype by environment interaction (GEI) multi-locational yield trials (MLYT) enables researchers to identify locations which are efficient in distinguishing tested genotypes, which are ideal across the test-locations as well as environments which are good representatives of the target regions of interest. The main objective of the study was to assess the genotype by environment interaction on grain yield stability of promising sorghum genotypes across five diverse environments of Zimbabwe. Sorghum yield data of twenty-seven cultivars was obtained from the replicated trials. After performing a pooled analysis of variance for grain yield across five diverse environments during the 2013/14 rainy season, the GxE interaction was significant (P<0.001), and this justified need for testing for GEI components using the GGE biplot analysis to enhance the understanding the effects of components. The results revealed that three mega-environments were identifiable which are Matopos, Save-Valley and Kadoma falling in one mega-environment, then Makoholi was identified as a second mega-environment and then Gwebi was identified as the third mega-environment. Gwebi had the most discriminating ability and good representativeness whereby Save Valley had a poor discriminating ability as well as least representativeness

Germination performance of tobacco varieties in response to different water potentials, priming and post - priming storage durations

Sub optimal seed germination and seedling establishment are major problems in tbacco (Nicotiana tabacum L) transplant production maybe due to dormancy, low soil moisture and poor seed to media contact in the float tray system . Seed priming in which seeds imbibe water or osmotic solutions followed by drying offers rapid germination and uniform seedling establishment

Evaluation and selection of taro [Colocasia esculentra (L.) Schott] accessions under dryland conditions in South Africa

Published online: 08 Oct 2018Taro [Colocasia esculenta (L.) Schott] is an important underutilised staple food crop in South Africa, with a lot of potential to address food insecurity among poor rural households. Development of high yielding stable taro cultivars is one of the most important goals of plant breeders. Twenty-nine taro accessions collected from major taro producing regions of the country were evaluated for growth performance, yield potential and stability under dryland conditions at two sites (Umbumbulu and Roodeplaat) in 2013, 2014 and 2015 cropping seasons. The experiment was laid in a randomised complete block design replicated three times. Growth and yield traits were measured. Analysis of variance and correlation analysis was done on all measured traits. The genotype by environment interaction was analysed using additive main effects and multiplicative interaction (AMMI). As a result, significant variation was observed for most of the traits except number of leaves and leaf width as well as number of suckers, while all the traits showed significant variation for location by year interaction. Number of corms showed significant variation for location by year by genotype interaction among all the traits evaluated. Genotype effect was highly significant (p < .01) on plant height, corm length, number of corms and significant (p < .05) on yield. The significant difference between genotypes for these traits proves that there was a genetic variability and there is a scope for selection. The correlation study also reveals that majority of the characters were positively correlated with each other. Total yield was positively and highly significantly (p < .01) correlated with all the measured traits. AMMI was effective in identifying stable genotypes. The top ranking cultivars per environment may be considered for cultivation under the specific environment, the stable cultivars may be considered for cultivation across all the taro growing regions