Guar resilience in water‐restricted production

Abstract

Guar [Cyamopsis tetragonoloba (L.) Taub] is an alternative crop in the Southern High Plains that thrives in semi-arid regions, due to its low water input requirements. Field experiments were conducted in 2017 and 2018 at New Deal, TX, to evaluate the response of guar ('Matador') to four levels of deficit irrigation (DI; extreme, 51 mm; severe, 127 mm; moderate, 203 mm; and mild, 279 mm). Soil moisture extraction patterns, plant height, leaf area index, yield components, seed yield, harvest index (HI), agronomic water use efficiency (AWUE), and irrigation WUE (IWUE) were measured among the irrigation levels. In both years, guar grown under extreme and severe DI extracted a major portion of the water from the 50-to-100-cm soil depth. Water deficit reduced plant height, leaf area index, and number of pods per plant in both years. However, the IWUE and 1,000-seed weight increased with reduced irrigation. There were no significant differences in seed yield, HI, and AWUE among treatments as a result of a tradeoff between increased seed weight with low pod production under lower DI treatments and increased pod production with low seed weight under higher DI treatments. Guar extracted water deeper in the soil and produced adequate numbers of pods per plant in balance with the source organ capacity to allocate resources toward optimal seed development. Our research offers valuable information about root exploration and development of larger seeds as compensatory mechanisms that can be further explored to improve the adaptability of guar under water-restricted production conditions.

Growth and Performance of Guar (Cyamopsis tetragonoloba (L.) Taub.) Genotypes under Various Irrigation Regimes with and without Biogenic Silica Amendment in Arid Southwest US

“…In general, growth parameters such as plant height and above-ground dry biomass at maturity were higher under the normal irrigation (I 1 ) regime, where no stress was experienced by guar plants, as compared to the reduced irrigation regimes (I 2 , I 3 , and I 4 ) (Table 1). These results are in accordance with previous studies that reported similar results [19,40]. It is interesting to note that although the irrigation regimes differed in imposing water stress during the reproductive stage, the water stress impacted plant height and above-ground biomass.…”

“…Due to its potential as an alternative crop in the Southwest US and a renewed interest in guar production, research on various aspects of guar production has recently gained impetus in the Southwest US [9][10][11][12][13][14][15][16][17]. A few recent studies have focused on the response of guar to irrigation level and shown the adaptability of guar under deficit irrigation conditions [18,19]. However, no studies have looked at deficit irrigation impacts on guar in the study region in combination with soil amendments such as biogenic silica in the region.…”