Heat Tolerance of Durum Wheat (Tritcum durum Desf.) Elite Germplasm Tested along the Senegal River

Abstract

The research is financed by Swedish Research Council (Vetenskapsradet) U-Forsk2013, "Deployment of molecular durum breeding to the Senegal Basin: capacity building to face global warming". AbstractThe Senegal River basin (Guinea, Mali, Mauritania, and Senegal) is a key agricultural production area in sub-Saharan Africa. Here, rice fields are left fallow during the cooler winter season, when the night temperatures reach 16 °C but the maximum daily temperatures remain above 30 °C. This season was used for the first time to conduct multi-environmental trials of durum wheat. Twenty-four elite breeding lines and cultivars were tested for adaptation during seasons 2014-15 and 2015-16 at two stations: Kaedi, Mauritania and Fanaye, Senegal. Phenological traits, grain yield and its components were recorded. Top grain yield was recorded at 5,330 kg ha -1 and the average yield at 2,484 kg ha -1 . The season lasted just 90 days from sowing to harvest. Dissection of the yield in its components revealed that biomass and spike fertility (i.e. number of seeds produced per spike) were the most critical traits for adaptation to these warm conditions. This second trait was confirmed in a validation experiment conducted in 2016-17 at the same two sites. Genotype × environment interaction was dissected by AMMI model, and the derived IPC values used to derive an 'AMMI wide adaptation index' (AWAI) to asses yield stability. The use of a selection index that combined adjusted means of yield and AWAI identified three genotypes as the most stable and high yielding: 'Bani Suef 5', 'DAWRyT118', and 'DAWRyT123'. The last two genotypes were also confirmed among the best in a validation trial conducted in season 2016-17. The data presented here are meant to introduce to the breeding community the use of these two research stations along the Senegal River for assessing heat tolerance of wheat or other winter cereals, as well as presenting two new ideal germplasm sources for heat tolerance, and the identification of spike fertility as the key trait controlling adaptation to heat stress.

Durum Wheat Breeding: In the Heat of the Senegal River

“…Further, the AMMI distribution of G × E effects (Figure 3) confirmed the discrimination capacity of these four heat prone environments. A similar conclusion was reached by Sall et al [5] when testing 24 modern lines under the same environmental conditions. In fact, GY at FAN16 and KED16 were 51% and 24% lower compared to the timely sown season 2014-2015 at the same sites, respectively.…”

“…In FAN16 the germplasm was exposed to the highest average temperatures (34 • C) during flowering, while it was lower (31 • C) in FAN15. This result shows the level of damage that the increase of just 3 • C in temperature can cause to the productivity of durum wheat if it occurs at the time of heading, as reported in Sall et al [5]. However, a 12% reduction in moisture was also imposed between FAN15 and FAN16, which can account for a portion of the variation in GY.…”

“…It occurs along the Senegal River Basin, with temperatures constantly above 30 • C throughout the wheat growing cycle and begin to rise further at the end of the season in late February to early March [5]. A durum wheat panel was investigated here under different sowing dates and amounts of water inputs across sites and years.…”

“…Detailed information on these sites and their discrimination ability is presented in Sall et al [5]. Briefly, temperatures in FAN15 were 32 • C average maximum and 15 • C average minimum, with peaks of 38 • C, while in FAN16 average maximum was 34 • C and average minimum at 15 • C, with peaks of 40 • C. These differences were mostly due to a delay of planting date from the 6th to the 17th of December in the second growing season.…”

“…As most of the farmers in the region depend on their fields to provide them with food, crop rotations can only be realistically practiced between staple crops. The introduction of high-yielding and adapted wheat cultivars would then provide an ideal complementation to rice [5]. This concept was also echoed by the Ministry of Agriculture of Senegal, who asked for international help to increase the amount of wheat grown along the Senegal River and for the release of high yielding cultivars well-adapted to this region [6].…”