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Potato cultivars grown in Rwanda are very old, low yielding and not amenable to food processing. High yielding and late blight tolerant cultivars for this country should be evaluated at different agro-ecozones prior to releasing them to farmers, who are yet to be integrated into potato breeding. The objectives of this study were to assess farmers’ preferred traits in potato cultivars and to gather knowledge from farmers about potato clones bred in Rwanda. Four respondents per village in 36 villages each for the districts of Musanze, Burera and Nyamagabe participated in the survey, whose questionnaire was about farm size, gender balance, land allocated to potatoes and other main crops, potato “seed” sourcing, potato production constraints and most important potato attributes. Potato was rated as the most important food and cash crop. ‘Kirundo’, ‘Cruza’, ‘Mabondo’ and ‘Victoria’ were the most popular cultivars. Among them, Mabondo’ was the most resistant to the oomycete Phytophthora infestans causing late blight. Potato production in Rwanda is limited by lack of improved cultivars, high temperature, drought, acidic soil, pathogens, insects, weeds, inadequate storage of tubers as planting material, post-harvest technology, low market price of tubers at harvest, lack of access to credit, climate change, and gaps such as inadequate fertilizer and fungicide applications. The most important cultivar attributes were high tuber yield, host plant resistance and high specific gravity or dry matter.

The global production of durum wheat (Triticum durumDesf.) is hindered by a constant rise in the frequency of severe heat stress. Three different germplasm panels were investigated under a range of heat stress to identify tolerant germplasm. The ‘discovery panel’ was field tested in the south of Morocco and along the Senegal River implementing a mild-to-strong North-South heat stress gradient. A subset of this same panel was also exposed to simulated terminal heat stress by applying plastic tunnels at the time of flowering. The ‘investigation panel’ and a ‘validation panel’ were field tested along the Senegal River under >32°C temperature throughout the season. Grain yield and its components were recorded at each site and a heat stress susceptibility index (HSI) was calculated. A total of 7,652 polymorphic single nucleotide polymorphisms (SNPs) defined the diversity of the first panel, while 5,642 SNPs defined the ‘investigation panel’. Genome-wide association study revealed that 36 quantitative trat loci were associated with the target traits in the ‘discovery’ panel, of which five were confirmed in the ‘subset’ tested with plastic tunnels and in the ‘investigation panel’. A haplotype study confirmed that Q.icd.Heat.003-1A, Q.icd.Heat.007-1B and Q.icd.Heat.016-3B are additive in nature and carrying the positive alleles at all three loci resulted in a 17% higher grain yield under heat stress. The underlying SNPs were converted into Kompetitive Allele Specific PCR (KASP) markers and tested on the ‘validation’ panel, confirming that each explained 4 to 9% of the phenotypic variation for grain yield under heat stress.