Temperature is a major abiotic stress limiting plant growth. Thermotolerance evaluation during germination and early growth may help identify adaptable genotypes of new crops. Two studies were conducted to evaluate temperature effects on 12 Brassica carinata genotypes during germination and early growth. During germination, genotype AX17004 was both the most cold- and heat-tolerant. During early-season growth (35 d after seeding), there were temperature and genotype effects on shoot, root, and physiological components. Cumulative low- and high-temperature response indices, and cumulative root and shoot response indices were related, indicating the importance of these traits. Genotype AX17006 was identified as heat tolerant, and AX17009 as cold tolerant during early-season growth. When genotypes were grouped according to breed types, hybrids generally had better responses than the inbred lines, and double haploids and the check responses were intermediate. These studies provided rapid results that will reduce the number of genotypes assessed in field studies.

Individual and multiple stress factor effects of temperature on cotton growth and development were studied in four cotton cultivars. In Experiment I, seedling emergence rate and shoot and root morphological growth traits were measured on plants grown at five day/night temperatures from 20/12 to 40/32 °C. In Experiment II, multiple stress factors (CO2, temperature, UV-B radiation) and their interactions were evaluated during the seedling growth stage. Seed emergence and above- and below-ground growth and developmental traits were recorded in both experiments. Linear (TM-1 and PHY496W3R) and quadratic (DP1522B2XF and ST47447) functions best described seed emergence rate with an increase in temperature. Similar responses were also observed for many root traits among the cultivars. Based on vigor and principal component analysis, DP1522B2XF was identified as the most tolerant, PHY496W3R and ST4747GLB2 as moderately tolerant, and TM-1 as the least tolerant cultivar to multiple environmental stresses.

Seed-placed phosphorus (P) and sulphur (S) fertilizers can reduce canola plant stands. Field studies were conducted to determine the effect of various sources and rates of seed-placed P and S fertilizers on canola plant stand, early season biomass accumulation and seed yield. Conventional granular P and S blends increased the risk of seedling damage, but increased the frequency of yield response. Liquid fertilizers were similar in seedling damage but generally less effective in increasing seed yield compared to granular fertilizers. Novel fertilizers were more seed-safe but less reliable than conventional sources in increasing seed yield. A growth room experiment was conducted to determine the effect of soils from different landscape positions on the toxicity of seed-placed ammonium sulphate (AS) and monoammonium phosphate (MAP). Canola emergence was reduced and delayed by seed-placed MAP and AS. Ammonium sulphate in particular has a high risk of NH3 toxicity on calcareous hilltop soils

Seed-placed phosphorus (P) and sulphur (S) fertilizers can reduce canola plant stands. Field studies were conducted to determine the effect of various sources and rates of seed-placed P and S fertilizers on canola plant stand, early season biomass accumulation and seed yield. Conventional granular P and S blends increased the risk of seedling damage, but increased the frequency of yield response. Liquid fertilizers were similar in seedling damage but generally less effective in increasing seed yield compared to granular fertilizers. Novel fertilizers were more seed-safe but less reliable than conventional sources in increasing seed yield. A growth room experiment was conducted to determine the effect of soils from different landscape positions on the toxicity of seed-placed ammonium sulphate (AS) and monoammonium phosphate (MAP). Canola emergence was reduced and delayed by seed-placed MAP and AS. Ammonium sulphate in particular has a high risk of NH3 toxicity on calcareous hilltop soils

Earlier planting to escape summer drought and high temperature has increased the importance of cold tolerance in corn. The objectives of this study were to assess cold tolerance among the corn hybrids using morpho-physiological traits and to classify hybrids into different groups of tolerance. Corn hybrids were subjected to optimum, low, and very low temperatures during seed emergence and seedling growth and morphological and physiological traits were assessed. Variability existed among the corn hybrids for the measured traits. Total, leaf and root weights and cumulative length and length per unit volume were the most important morphological traits in describing hybrid variability. Principle component analysis and total low temperature response index methods were used to categorize hybrid tolerance to low temperature. Based on relative scores assigned in this study and their yield potential in the niche environment, producer could select hybrids to maximize corn production in an early planting production system.

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