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Malawi, in south-eastern Africa, is one of the poorest countries in the world. Food security in the country hinges on rainfed systems in which maize and sorghum are staple cereals and groundnut and pigeonpea are now major grain legume crops. While the country has experienced a considerable reduction in forest lands, population growth and demand for food production have seen an increase in the area dedicated to agricultural crops. From 2010, pigeonpea developed into a major export crop, and is commonly intercropped with cereals or grown in double-up legume systems. Information on the spatial extent of these crops is useful for estimating food supply, understanding export potential, and planning policy changes as examples of various applications. Remote sensing analysis offers a number of efficient approaches to deliver spatial, reproducible data on land use and land cover (LULC) and changes therein. Moderate Resolution Imaging Spectroradiometer (MODIS) products (fortnightly and monthly) and derived phenological parameters assist in mapping cropland areas during the agricultural season, with explicit focus on redistributed farmland. Owing to its low revisit time and the availability of long-term period data, MODIS offers several advantages, e.g., the possibility of obtaining cloud-free Normalized Difference Vegetation Index (NDVI) profile and an analysis using one methodology applied to one sensor at regular acquisition dates, avoiding incomparable results. To assess the expansion of areas used in the production of pigeonpea and groundnut resulting from the release of new varieties, the spatial distribution of cropland areas was mapped using MODIS NDVI 16-day time-series products (MOD13Q1) at a spatial resolution of 250 m for the years 2010–2011 and 2016–2017. The resultant cropland extent map was validated using intensive ground survey data. Pigeonpea is mostly grown in the southern dry districts of Mulanje, Phalombe, Chiradzulu, Blantyre and Mwanza and parts of Balaka and Chikwawa as a groundnut-pigeonpea intercrop, and sorghum-pigeonpea intercrop in Mzimba district. By 2016, groundnut extent had increased in Mwanza, Mulanje, and Phalombe and fallen in Mzimba. The result indicates that the area planted with pigeonpea had increased by 29% (75,000 ha) from 2010–2011 to 2016–2017. Pigeonpea expansion in recent years has resulted from major export opportunities to Asian countries like India, and its consumption by Asian expatriates all over the world. This study provides useful information for policy changes and the prioritization of resources allocated to sustainable food production and to support smallholder farmers.

Early‐maturing rapeseed (Brassica napus L.) can alleviate the seasonal conflict between double‐season rice (Oryza sativa L.) and rapeseed in the Yangtze River basin. In this study, the early‐maturing rapeseed ‘Shengguang 127’ and intermediate‐maturing cultivar ‘Huayouza 9’ (control) were sown on 2 October under five different planting densities (150,000 [D1], 300,000 [D2], 450,000 [D3], 600,000 [D4], and 750,000 plants ha−1 [D5]) during two growing seasons. The patterns of change in growth and development, yield, and yield components were investigated systematically to reveal the light energy and temperature production efficiencies and to quantify the ideal plant density for the early‐maturing cultivar. The results showed that the early‐maturing genotype advanced the whole growth period by 3 to 5 d under the same densities, compared with those of the intermediate‐maturing genotype. The yield and population dry matter weight of both cultivars decreased after an initial increase, with the density increased initially from the D1 to D3 treatment, where it reached a maximum, and then decreased to the D5 treatment. Similar trends were observed in the light and temperature production efficiencies. Under the same densities, the production efficiencies of light energy and temperature in Shengguang 127 were 14.7 to 24.2% higher than those of the control, respectively; the yield and harvest indices in Shengguang 127 were significantly higher than those in Huayouza 9, which was attributed to the significantly higher 1000‐seed weight. These results provide a theoretical basis for the agronomic management and breeding of high‐yielding traits of early‐maturing rapeseed in the Yangtze River basin.

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The objectives of this study were to evaluate genetic variation among kabuli chickpea genotypes and to determine the relationships among agronomic traits with seed yield. Field experiments were conducted during the long and short rain seasons of 2013 using alpha lattice design in triplicate. Data on agro-morphological traits were recorded using descriptors for chickpea and analysed using SAS 2013 and Genstat 2014. There were highly significant (p < 0.001) variations among genotypes and genotype by environment interactions for all studied traits. The top five high yielding genotypes were ICCV 05315, ICC 13461, ICCV 07313, ICC 13764 and ICCV 00302. Genotypes ranking for most agronomic traits varied across environments which indicated a crossover type of genotype by environment interactions. Evaluated genotypes were polymorphic for six qualitative traits. Seed yield ha -1 was positively and significantly (p < 0.05) correlated with biomass yield ha -1 , pods plant -1 , plant canopy width and secondary branches plant -1 . These characters could be used for indirect selection of high yielding genotypes. The first principal component explained 57% of the total variation and was associated with days to 50% flowering and podding, plant canopy width, plant height, number of primary and secondary branches plant -1 , days to 75% maturity, number of pods plant -1 and biomass yield ha -1 as positive contributors. The documented information on genetic variation and association of agronomic traits with seed yield can be exploited to devise suitable breeding strategies and chickpea germplasm conservation.