Novel sources of drought tolerance from landraces and wild sorghum relatives

Abstract

Sorghum (Sorghum bicolor [L.] Moench) is the fifth most important cereal crop worldwide and second after maize (Zea mays L.) in Kenya. It is an important food security crop in arid and semi-arid lands, where its production potential is hampered by drought. Drought tolerance can be measured by a plant's ability to resist premature senescence, often described as stay-green. This study was carried out with the objective of identifying novel stay-green trait among wild and landrace genotypes of sorghum. Forty-four sorghum genotypes that included 16 improved, nine landraces, and 17 wild relatives of sorghum alongside known stay-green sources, B35 and E36-1, were evaluated under well-watered and water-stressed conditions in an alpha-lattice design of three replications. Data was collected on plant height (PHT), flag leaf area (FLA), panicle weight (PWT), 100-seed weight (HSW), relative chlorophyll content (RCC), number of green leaves at maturity (GLAM), days to 50% flowering (DFL), and grain yield (YLD). Genetic diversity was determined using diversity arrays technology (DArT) sequencing and quality control (QC) markers were generated using a java script. Lodoka, a landrace, was the most drought-tolerant genotype, recorded the highest numbers of RCC and GLAM, and outperformed B35 and E36-1 in yield under water-stress and well-watered conditions. The RCC was highly correlated with GLAM (r = .71) and with yield-related traits, HSW (r = .85), PWT (r = .82), and YLD (r = .78). All traits revealed high heritability (broad-sense) ranging from 60.14 to 98.4% for RCC and DFL, respectively. These results confirm earlier reports that wild relatives and landraces are a good source of drought tolerance alleles.

Genotypic Variation in Cultivated and Wild Sorghum Genotypes in Response to Striga hermonthica Infestation

“…The older sources of drought tolerance will, however, need to be replaced with new superior performing genotypes such as F6YQ212 × B35 and ICSVIII IN × LODOKA identified in the current study. OKABIR, AKUOR-ACHOT, and LODOKA are landraces, which have also been recently reported to perform better than B35 and E36-1 under drought conditions (Ochieng et al, 2020 ). While LODOKA clustered with MACIA, both OKABIR and AKUOR-ACHOT appeared to be distantly related to MACIA, B35, and E36-1 and will therefore be good alternative sources of both drought and Striga tolerance.…”

“…The only other resistant check that clustered differently was N13, a durra sorghum from India, which is known to stimulate Striga germination but forms a mechanical barrier to Striga penetration (Maiti et al, 1984 ; Mohemed et al, 2016 ; Mbuvi et al, 2017 ). Genotype N13 grouped together with B35, a drought-tolerant variety, which has its origins in Ethiopia (Ochieng et al, 2020 ).…”

“…Molecular data of all the 37 parental genotypes in Table 1 , which consisted of 17 wild accessions, 8 landraces, and 12 improved varieties, were generated for the genetic diversity analysis. DNA extraction, genotyping, and filtering of raw SNPs were performed as described by Ochieng et al ( 2020 ). A neighbor-joining (NJ) dendrogram was generated using the Trait Analysis by aSSociation, Evolution, and Linkage (TASSEL) software version 5.2.67 (Bradbury et al, 2007 ).…”

Crop Science special issue: Adapting agriculture to climate change: A walk on the wild side

“…Aberkane et al (2021), in "Evaluation of durum wheat lines derived from interspecific crosses under drought and heat stress," conclude that gene introgression from wild diploid and wild tetraploid wheat-derived materials pays off and can increase wheat resilience. Drought tolerant genotypes with high values of relative chlorophyll content and more green leaves at maturity have been identified by Ochieng et al (2021), in "Novel sources of drought tolerance from landraces and wild sorghum relatives". Kouassi et al (2021), used an original approach to estimate drought tolerance scores for vegetative growth and yield related traits in "Genetic parameters of drought tolerance for agromorphological traits in eggplant, wild relatives, and interspecific hybrids."…”

“…Drought tolerant genotypes with high values of relative chlorophyll content and more green leaves at maturity have been identified by Ochieng et al. (2021), in ” Novel sources of drought tolerance from landraces and wild sorghum relatives “. Kouassi et al.…”