Quantitative trait loci (QTLs) for water use and crop production traits co-locate with major QTL for tolerance to water deficit in a fine-mapping population of pearl millet (Pennisetum glaucum L. R.Br.)

Abstract

Four genetic regions associated with water use traits, measured at different levels of plant organization, and with agronomic traits were identified within a previously reported region for terminal water deficit adaptation on linkage group 2. Close linkages between these traits showed the value of phenotyping both for agronomic and secondary traits to better understand plant productive processes. Water saving traits are critical for water stress adaptation of pearl millet, whereas maximizing water use is key to the absence of stress. This research aimed at demonstrating the close relationship between traits measured at different levels of plant organization, some putatively involved in water stress adaptation, and those responsible for agronomic performance. A fine-mapping population of pearl millet, segregating for a previously identified quantitative trait locus (QTL) for adaptation to terminal drought stress on LG02, was phenotyped for traits at different levels of plant organization in different experimental environments (pot culture, high-throughput phenotyping platform, lysimeters, and field). The linkages among traits across the experimental systems were analysed using principal component analysis and QTL co-localization approach. Four regions within the LG02-QTL were found and revealed substantial co-mapping of water use and agronomic traits. These regions, identified across experimental systems, provided genetic evidence of the tight linkages between traits phenotyped at a lower level of plant organization and agronomic traits assessed in the field, therefore deepening our understanding of complex traits and then benefiting both geneticists and breeders. In short: (1) under no/mild stress conditions, increasing biomass and tiller production increased water use and eventually yield; (2) under severe stress conditions, water savings at vegetative stage, from lower plant vigour and fewer tillers in that population, led to more water available during grain filling, expression of stay-green phenotypes, and higher yield.

Aquaporins are main contributors to root hydraulic conductivity in pearl millet [Pennisetum glaucum (L) R. Br.]

“…No XIP were identified, which confirm the absence of isoforms from this family in the monocotyledon clade [8]. The number of AQP identified in pearl millet is similar to what has been observed in Arabidopsis (35) [58], rice (33) [23] and maize (31) [20]. Interestingly, AQP genes were over-represented on Chromosome 3 with fourteen genes (Fig 3).…”

“…AQP also have important roles in plant growth, CO 2 fixation, nutrient allocation, reproduction or biotic interactions [8]. In recent years, AQP functions in plant water relations have received more attention as a potential target for crop improvement [28][29][30][31][32][33]. For instance, AQP could contribute to balancing root water transport with transpiration in soybean under high evaporative demand [34].…”

Functional Dissection of the Chickpea (Cicer arietinum L.) Stay-Green Phenotype Associated with Molecular Variation at an Ortholog of Mendel’s I Gene for Cotyledon Color: Implications for Crop Production and Carotenoid Biofortification

“…In many of the semiarid rain-fed agrisystems, one of the main limiting factors to crop productivity is soil moisture deficit [2,8,57,58,59,60]. To understand plant responses to decreased soil moisture, we have generated substantial evidence on plant functions that contribute to crop adaptations in these environments [61,62,63,64,65]. In the present study we evaluated whether stay-green phenotype in chickpea underlined by CaStGR1 gene might be functionally involved in any important environmental adaptations (i.e., responsiveness to soil and atmospheric drought).…”

Inter-relação de técnica de manejo de água e solo aplicadas a cultura do milheto: uma revisão

“…Além disso, estudo com milheto em condições de cultivo de sequeiro têm demonstrado, que a adubação com esterco animal pode elevar o risco do cultivo, uma vez que, a adubação promove um rápido crescimento da parte aérea, que quando submetida à deficiência hídrica entra rapidamente em senescência (Affholder, 1995). Uma maior emissão de perfilhos promovida por um manejo nutricional equilibrado, também promoverá um maior consumo de água (Tharanya et al, 2018). Quando a área foliar da planta aumenta há um incremento na evapotranspiração do cultivo, pois uma maior área foliar começa a transpirar (Santos et al, 2018).…”

“…O seu sistema radicular agressivo é capaz de explorar um grande volume de solo, o que torna a planta muito eficiente na absorção de água, carbono e nutrientes, explicando em grande parte a sua tolerância ao estresse hídrico e seu bom desenvolvimento em solos salinos de baixa fertilidade e pH (Aguiar et al, 2012;Kumar et al, 2018). Em suas características morfológicas, existe uma associação entre o aumento do sistema radicular com a produção de grãos, fitomassa e transpiração do milheto (Tharanya et al, 2018). Development, v. 9, n. 7, e569974503, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i7.4503 O milheto por ser adaptado às altas temperaturas e déficit hídrico moderado (Nelson et al, 2018), é uma cultura majoritária nas projeções de mudanças climáticas e solos salinos (Kumar et al, 2018).…”