Climate change is expected to aggravate the eﬀects of drought, heat and combined drought and heat stresses. An important step in developing ‘climate smart’ maize varieties is to identify germplasmwithgoodlevelsoftolerancetotheabioticstresses. Theprimaryobjectiveofthisstudywas toidentifylandraceswithcombinedhighyieldpotentialanddesirablesecondarytraitsunderdrought, heat and combined drought and heat stresses. Thirty-three landraces from Burkina Faso (6), Ghana (6) and Togo (21), and three drought-tolerant populations/varieties from the Maize Improvement Program at the International Institute of Tropical Agriculture were evaluated under three conditions, namely managed drought stress, heat stress and combined drought and heat stress, with optimal growing conditions as control, for two years. The phenotypic and genetic correlations between grain yield of the diﬀerent treatments were very weak, suggesting the presence of independent genetic control of yield to these stresses. However, grain yield under heat and combined drought and heat stresses were highly and positively correlated, indicating that heat-tolerant genotypes would most likely tolerate combined drought and stress. Yield reduction averaged 46% under managed drought stress, 55% under heat stress, and 66% under combined drought and heat stress, which reﬂected hypo-additive eﬀect of drought and heat stress on grain yield of the maize accessions. Accession GH-3505 was highly tolerant to drought, while GH-4859 and TZm-1353 were tolerant to the three stresses. These landrace accessions can be invaluable sources of genes/alleles for breeding for adaptation of maize to climate change.
Posts Tagged ‘climate change’
Swedish journalists Eric Abel and Anna Liljemalm who are writing a book on climate change and seed visited the Stress Tolerant Maize for Africa project in Kenya from Sept. 9-11, 2019.
We met some farmers who adopted drought tolerant maize hybrid SAWA from Dryland Seeds Ltd (DSL) in drought-prone Makueni county.
Dolly Muatha is a 49 years-old demo farmer with four children.
Because her fields are well placed near the road, she has benefited for the last three years from DSL support to demonstrate the yield potential of SAWA DT maize in this terraced landscape.
Dolly likes SAWA ‘’because it produces 2 to three beautiful cobs and it matures early. In case rains stop when the maize is at knee height, even before tassel and silks form, that is where you see its potential compared to non-drought tolerant varieties.’’
Alex Somba 45 year-old farmer near Wote saw how SAWA performed at Muatha’s farm and tried it out in 2017.
He usually practices dry planting from October 1, as rains usually start around the third or end October, until end of the year.
‘’SAWA beats other popular hybrids because of its early maturity and drought tolerance. It resists well to Grey Leaf Spot and grain stores well, resists weevil.’’
‘’If rains start end of October and after 2 weeks of rains there is a dry spell of 2 weeks, other varieties will perform badly whereas SAWA copes relatively well with such erratic rains patterns,’’ he added.
Providing good agronomic advice to the farmers is important to benefit fully from new varieties. Joyce, DSL field officer pointed out that ‘’ a good advice I usually give for farmers like Alex is optimum crop spacing.’’ For better yields, she would advise to practice 20cm x 30 cm spacing, one seed at a time. Traditionally farmers would put up to 5 seeds per planting hole, which will generate small cobs and much lower yields.