Guar (Cyamopsis tetragonoloba L.) is a drought‐tolerant summer annual legume that can be grown for forage, green pods, or seeds. Galactomannans use in various industries such as food, cosmetic, paper, and oil etc. has attracted the guar production for seed. Currently, most of the United States’ demand for guar is met through imports. Preliminary research has shown that guar can be potentially grown in semiarid irrigated conditions in southern New Mexico (NM). A 2‐yr field study was conducted from 2014–2015 to evaluate stand establishment, physiology, and yield performance of eight guar genotypes under four planting dates in southern NM. In both years, mid‐June planting resulted in better stand establishment by having higher plant density than late‐April and mid‐May plantings. The mid‐June planting resulted in higher photosynthetic rate (Pn) compared to late‐April and early July plantings. Transpiration rate (Tr), leaf area index (LAI), clusters plant−1, pods plant−1, and seeds plant−1 were also higher for mid‐June planting compared to mid‐May and early July plantings in both years. Across genotypes and years, mid‐June planting produced 13, 27, and 45% higher seed yield than late‐April, mid‐May, and early July plantings. Across planting dates, genotype NMSU‐15‐G1 had highest seed yield among all genotypes in both years; however, it did not differ significantly from cultivar Matador. Introduction lines and cultivar Matador took more days to reach various stages. The mid‐June planting showed early maturity. Guar planted under mid‐June planting appears to increase seed yield along with having early maturity in southern NM. Planting date had a significant effect on guar seed yield. Significant genotypic variation for seed yield was observed across planting dates. Planting dates and genotypes showed a significant interaction for guar seed yield. Mid‐June planting increased guar seed yield over other tested planting dates.

Guar is a drought and salt tolerant summer annual legume, which could be a potential alternative crop in the semi-arid Southern High Plains. Increased use of guar gum in oil industries has increased the demand of guar globally. Planting date effects on stand establishment, physiological parameters, and yield formation of guar genotypes were investigated at the New Mexico State University's Agricultural Science Center at Clovis, NM for two seasons (2014 and 2015). Four guar genotypes (HES 1123, Kinman, Lewis, and Matador) were tested under three planting dates (June 18, July 7, and July 22 in 2014; and June 18, July 6, and July 20 in 2015). Higher temperature and rainfall were recorded under mid-June planting than early-July and late-July plantings. Guar planted under mid-June had better stand establishment as shown by the higher number of plants m −2 , better physiology as revealed by higher photosynthetic rate (P n ), transpiration rate (T r ), leaf area index (LAI), and SPAD values than early-July and late-July plantings. Guar planted under mid-June resulted in taller plants, and therefore, produced higher plant biomass than both of the July plantings. Yield attributing characteristics including clusters plant −1 , pods plant −1 , seeds plant −1 , seed spod −1 , 1000 seed weight, and harvest index (HI) were highest under mid-June planting followed by the early-July and late-July plantings, respectively. The mid-June planting in-* Corresponding author. S. Singla et al. 1247creased seed yield by 26% and 55% over early-July and late-July (1399 vs. 1111 and 903 kg•ha −1 ) plantings, respectively in 2014; while the same increase in 2015 was 51% and 243% (1308 vs. 868 and 381 kg•ha −1 ), respectively. These results indicate that delaying planting beyond mid-June is detrimental to guar productivity. However, genotypes did not show any significant variation in their performance. Overall, warmer growing conditions and more precipitation under mid-June planting caused better growth and yield formation of guar genotypes.