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Acala‐type cottons (Gossypium hirsutum L.) released from New Mexico have contributed significantly to the development of commercial upland cultivars in the United States. The objective of this study was to assess the genetic gain in the breeding program between 1926 and 2000 through a combined analysis of field data on representative Acala cultivars from New Mexico and California obtained in multiple tests over years. From 1926 (‘Acala Original’) to 2000 (‘Acala 1517‐99’), the overall lint yield improvement was estimated at 3.2 kg ha−1 yr−1 but was 6.4 kg ha−1 yr−1 in 1926 to 1970 and 10.2 kg ha−1 yr−1 in 1975 to 2000. The yield improvement was accompanied by an increase in lint percentage (from 37 to 40%), fiber strength (from 270 to 300 kN m−1 kg−1), and micronaire, but with reduced boll weight. Although there was an upward trend for fiber length and uniformity and a downward trend for short fiber content, the three traits remain stable. Comparing eight New Mexico Acala 1517 cultivars with nine California Acala cultivars bred during the same period (late 1930s to the 1970s), the former, as a group, had longer and stronger fibers but slightly lower lint percentage and elongation. The Acala 1517 cotton cultivars provide an excellent source of parental lines for developing cotton cultivars with enhanced fiber quality.

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Water limitation is a well-known problem for wheat plants. Lack of water affects their biomass and yield. This is the most conspicuous in case of crops causing severe uncertainty of agricultural productivity. Progress in breeding to improve drought tolerance has been limited by its high sensitivity to environmental factors, low heritability, and the complexity and size of wheat genome. In this study eight genotypes of bread wheat were used for screening them under three water regimes; control 100% Field Capacity (FC), 75% FC and 50% FC. Five drought resistance indices including Mean Productivity (MP), Tolerance Index (TOL), Drought Susceptibility index (DSI), Geometric Mean Productivity (MP) and Yield Stability Index (YSI) were calculated for each genotype based on grain yield under stress (50% FC) and normal (100% FC) conditions. Physiological parameters, chlorophyll content (SPAD values), proline accumulation and expression levels of drought related genes were analyzed in wheat plants at heading stage, comparing eight genotypes with different drought tolerance capacity. The imposed drought stress induced a decreasing of plant growth and chlorophyll content, a strong increase in proline and expression of drought related genes. The correlation coefficients showed that YSI, MP, DSI and GMP had the most desirable selection criteria for high yielding and drought tolerant genotypes. The development of molecular markers for physiological traits has made significant headway in recent years with the advancement of new technologies. Consequently, in our study the use of molecular markers; RAPD technique with 9 primers was detected 91 polymorphism alleles for the genotypes with 79.12% polymorphism. The most Polymorphic Information Content (PIC) value and polymorphism percentage was detected by OPA-07primer that showed the high score from bands 13 with polymorphism 69.23%. While, OPO-19 revealed low level from bands was 6 with percentage 83.33%. Also, OPA-02, OPA-04 and OPO-13 revealed 9 fragments with 77.78% polymorphism. While, primers OPB-07, OPB-10 and OPO-14 showed 11 bands with 81.82% polymorphism. The last primer revealed 12 bands with 75% polymorphism. Therefore, these recently developed techniques could be enable faster identification and characterization of drought-related gene(s).

Cotton has a production value of US$ 45.86 million in New Mexico (USDA-NASS 2018). In June 2019, 1-2% cotton seedlings with chlorotic, necrotic or wilted leaves, or root rot were observed in six Pima cotton fields in south Las Cruces, New Mexico. Roots from five symptomatic plants sampled in each field were washed free of the soil, surface-sterilized with 0.8% sodium hypochlorite, rinsed 2-3 times with sterile distilled water, and blotted dry with a paper towel. The sterilized tissues were then dissected and plated on acidified potato dextrose agar (PDA) and incubated for 5 days at 25℃ with a 12 h dark/light photoperiod. Fungal colonies that had similar morphology were consistently isolated at 70% isolation frequency. One representative isolate from each field was selected for the following analysis. Colonies were initially white and turned pinkish 5 days later on PDA. Dark orange pigments on the bottom of plates were observed after 7 days. On PDA, the macroconidia were slender, almost straight, 3-5 septa, and medium length with a size of 25.5-41.0 × 2.8-4.5 μm (n=30). The microconidia were abundant, 0-1 septa, and oval shaped, with a size of 5.5-11.0 × 2.0-3.2 μm (n=30). Sporodochia and chlamydospores were not observed. The pathogen was therefore identified as Fusarium fujikuroi (Leslie and Summerell 2006). Genomic DNA from the isolates was extracted, and a portion of the translation elongation factor EF-1α gene (GenBank accession nos. MN896942 to MN896947), β-tubulin gene (MN896949 to MN896954) and phosphate permease (PHO) gene (MN896956 to MN896961) were amplified and sequenced using the paired primers EF-1A/EF1885R, BT-100F/BT1828R, and PHO48F/PHO2034R, respectively (Ortiz et al. 2017). BLASTn analysis of the three genes of all the isolates showed 100% (1640/1640 bp, 1694/1694 bp, and 1872/1872 bp) identity to the reference isolate of F. fujikuroi TX75 (MH828026, MH827999, and MH828057, respectively) and 99% (1634/1640 bp, 1691/1694 bp, and 1863/1872 bp) identity to another isolate (GA1A-1-1) of F. fujikuroi (KY293654, KY293646, and KY293662, respectively). A phylogenetic analysis based on the concatenated sequences clustered the six isolates with the F. fujikuroi reference isolates at 100% bootstrap support, confirming the identity of the isolates. Pathogenicity of the six isolates was tested on Upland genotype PHY 725 RF and Pima genotype PHY 841 RF. Fifty microliter conidial suspension (5 × 105 conidia ml-1) of each isolate was pipetted onto the soil around the base of the seedlings at the 1st true-leaf stage. The experiment was performed twice. Initial symptoms of wilting cotyledons were observed 7 days after inoculation (DAI). All the isolates were pathogenic to the two genotypes, causing wilting and yellowing of the leaves, rot of the root, and eventually death of some plants at 30 DAI, similar to the symptoms observed in the field. No symptoms were observed on the control plants inoculated with sterile distilled water. The average foliar disease severity rating was 2.9 on PHY 725 RF and 1.6 on PHY 841 RF on a scale of 0 for no symptom to 5 for plant death. F. fujikuroi was successfully reisolated from the roots of symptomatic plants and was identical to the isolates used for the pathogenicity test. F. fujikuroi has been reported to cause root rot and wilt on soybean (Pedrozo et al. 2015; Zhao et al. 2020), bakanae disease on rice (Carter et al. 2008) and a seedling disease on cotton (Colyer 1988). To our knowledge, this is the first report of F. fujikuroi causing wilt on cotton seedlings in New Mexico and the U.S.