A wheat and barley test on the Bruce Church Ranch, Poston, Arizona, La Paz County, harvested June 8 & 9, 1987, gave crop and variety performance differences under grower management conditions. The top yielding barley variety was Fiesta, 6990 lbs /ac. The leading durum varieties were Turbo, Gem and Aldura. Durum wheat Westbred 881 was highest in protein (13.7 %). In red wheat varieties, yields ranged from 4660 to 5750 lbs/ac. The top three varieties were Baker, Probred and Yecora Rojo. Baker was highest in protein (14.6 %), followed by Yecora Rojo (14.2%). Continued testing over several years is necessary to assess variety performance under grower management conditions.

Aldura, Westbred Turbo and Westbred 881 were grown in four sites in three counties (Graham, Greenlee and Cochise) in southeastern Arizona to determine which would produce the largest income per acre. At an assumed 75 cent premium for Westbred 881 over a base of $5.25 per hundredweight, Aldura and Westbred Turbo generally out produced Westbred 881. Relative yields of the three varieties are shown for all locations.

Sixteen winter wheat varieties (including three hybrids) were evaluated in a randomized, complete block experiment, with four replications. Stephens, the standard variety grown in the area, was outyielded by four of the winter wheat cultivars, including two of the hybrids. The highest yielding cultivar was a hybrid, Bounty 100, which yielded 5853 pounds per acre (23% higher than Stephens).

Weed infestation is one of the yield limiting factors in crop production. Weeds have negative effect on crop growth and productivity due to competition, allelopathy or hosting other harmful organisms. For large-scale wheat production, the use of wide spectrum pre-emergence or post-emergence herbicides remains the most valuable weed control tool. In South Africa, annual grass weeds are a major wheat production constraint, which is usually managed through application of pre-emergence herbicides. Due to limited water availability and low soil moisture content, these herbicides can often become ineffective and result into high weed infestations, which then have to be managed by manual cultivation or post-emergence herbicidal applications. However, there are no effective selective post-emergence herbicides available to control grass weeds in wheat. There is also limited option to use broad-spectrum post-emergent herbicides because they non-selectively kill the crop and weeds. Consequently, the use of herbicide resistant crops is a viable weed management system in wheat production. Breeding herbicide resistant crop varieties would allow farmers to safely use post-emergence herbicides without damaging the crop. Subsequently yield and quality losses will be reduced significantly. Thus, the development of herbicide resistant crop varieties through mutation breeding is a novel approach for effective weed management under both small-scale and commercial farmers. Mutagenesis has been recognized as one of the most efficient method to induce genetic variation in plants. Through induced mutations, development of new variants is possible that could be manipulated in plant breeding programs. Mutation leads to alteration of various traits in crop plants including plant height, improved nutritional quality, shorter growing period, increased tolerance or resistance to abiotic and biotic stresses. Ethylmethanesulphonate (EMS) is one of the most widely used chemical mutagens to induce mutagenesis in crop plants. The objectives of this study were to: 1) determine the optimum EMS concentration, treatment temperature and duration that would provide desired germination percentage and vigorous and healthy seedlings for effective mutagenesis in wheat, 2) investigate variations in agro-morphological traits in two selected wheat varieties (SST56 and SST875) after EMS mutagenesis and 3) select herbicide resistant wheat germplasm after inducing genetic variation using EMS using two selected wheat varieties (SST56 and SST875). The objectives were achieved through three independent studies as outlined below: In the first study seeds of four selected wheat varieties (B936, B966, SST387 and SST875) were treated in two replicates with three EMS concentrations (0.3, 0.5, and 0.7%), three temperature regimes (30, 32.5 and 35 °C) at four time durations (0.5, 1, 1.5 and 2 hrs). Results showed highly significant interactions (P<0.01) among varieties, EMS concentrations, temperature and exposure time on seedling emergence, germination and seedling height. Seeds treated with the highest EMS dose (0.7%), temperature (35ºC) and long exposure time (2 hr) showed delayed emergence by 18 days. At 30ºC, 0.5hr and 0.3% EMS varieties B936, B966 and SST875 had early emergence (6 days). B936 and SST387 had 50% while B966 and SST875 had 53% and 57% germination, respectively. These results were observed at EMS level of 0.7%, 300C and 1.5 hr exposure time in B936 and EMS at 0.5%, 350C and 1.5 hr in B966. SST387 and SST875 required EMS dose at 0.5%, 32.50C and 2 hr treatment time. Other low or high treatment combinations were invariably ineffective comparedto untreated control. During the second study two selected varieties (SST56 and SST875) were subjected to EMS mutagenesis using 0.5% v/v EMS at 32.5oC for 1 hr. Field trials were carried out at Ukulinga research farm of the University of KwaZulu-Natal in the randomized complete block design with two replicates. Data on nine important agro-morphological traits were collected and analyzed using the analysis of variance (ANOVA), correlation and principal component analysis (PCA) procedures. Significant variations were found among the agro-morphological traits between M1 individuals compared to untreated checks. The mutagenesis significantly reduced seed germination in the field at 40% in both varieties. The treatment significantly delayed days to heading by 8 days and shortened days to maturity by 13 days in both varieties. EMS treatment also significantly reduced plant height at 18 cm in SST56 and 21 cm in SST875 and spike length reduced by ~2.5 cm in both varieties. Plant height had positive and significant correlation with number of tillers, number of seeds per spike, flag leaf length and 100 seed weight. However, it had negative correlation with the number of days to maturity. The PCA revealed that three principal components (PC1, PC2 and PC3) accounted to 57% of the total variations among the agro-morphological traits in both varieties. PC1 alone contributed to 27.7% of the variation which was well-correlated with plant height (0.767), tiller number (0.812), number of seeds per spike (0.599) and seed yield (0.720). PC2 explained 15.6% of the variation and well-correlated with germination percentage (0.784), spike length (0.554) and flag leaf length (0.772). PC3 accounted to 12.4% of the variation and had negative correlation with days to maturity (-0.730). In the last study, seeds of two selected wheat varieties (SST56 and SST875) were treated with EMS at 0.5% concentration for 2 hr at 32.5ºC. Treated seeds and comparative controls were planted at the experimental farm of the University of KwaZulu-Natal using the randomized complete block design. Four weeks after planting M1 plants and untreated standard checks were sprayed with two herbicides, i.e. metsulfuron-methyl and bromoxynil at three different doses viz. 2x, 4x and 8x above the recommended rate of 4 g ha-1 and 2 kg ha-1, respectively. Two weeks after the treatment herbicide resistance were assessed. Results showed significant difference among varieties, tested herbicides and doses used. The EMS treated wheat lines showed variable degree of herbicide resistance compared to untreated controls. Overall, the study established the requirement of variety specific EMS dose and treatment temperature and duration that could be used for inducing large-scale mutation to select targeted mutant individuals in wheat. Further, the study found that EMS has the potential to increase agro-morphological variations in wheat to select useful and novel mutants with desired phenotypic traits and herbicide resistance which will be subjected for further selections to identify stable and herbicide resistance lines. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.

Planting date is an important consideration when growing small grain varieties under reduced water use conditions. The objective of this study is to document interactions of planting date and varieties grown with a single irrigation near planting. Field studies were conducted at the Maricopa Agricultural Center during the 1988, 1989, and 1990 growing seasons. Six barley, durum, and wheat varieties were compared at four planting dates from November to February. Early November or early December planting dates were optimum. The relative performance of the varieties differed depending on the year and planting date. The highest yielding varieties over most planting dates were Solum and 6-39-1-1 (barleys), Mexicali (durum), and B85-277A and M83-39-18 (wheats). Improvement of barley, durum, and wheat genotypes for reduced water use conditions continues at the University of Arizona, and notable progress in durum and wheat performance has been achieved recently.

Yield trials were conducted at the Maricopa Agricultural Center during the 1990 -91 growing season. Barley, Durum and Wheat varieties as well as experimental lines from various seed companies were tested for yield performance. Gustoe and Sunbar 409 barleys, Turbo and Aldura durum wheats; and 911 and Klasic bread wheats were the highest yielding commercial varieties in this yield trial.

Planting date can have a tremendous effect on small grain yield. The purpose of this study is to document the interactions of planting date with current small grain varieties. Field studies were conducted at the Maricopa Agricultural Center over the 198$ 1989, and 1990 growing seasons. Six barley, durum and wheat varieties were compared at four planting dates from November to February. WestBred Gustoe was among the highest yielding barleys and WestBred Turbo was among the highest yielding durum regardless of planting date. The highest yielding wheat was WestBred 911 at the November plantings, Klasic at the December and January plantings, and Topaz and Klasic at the February plantings. The varieties also responded differentially to planting date in terms of plant height, kernel weight, heading and maturity date, but not test weight. This study demonstrates the importance of planting date in choosing a small grain variety.

A 12-inch row spacing is commonly used to evaluate small grain varieties at the Maricopa Agricultural Center and other experiment stations. The objective of this study was to document the interactions of varieties and row spacings. Sir barley, durum, and wheat varieties were planted in the 1989 and 1990 growing seasons at the Maricopa Agricultural Center at four planting dates (November, December, January, February) and 6 and 12-inch row spacings. At the December planting date, which is near optimum, WestBred 881 and Topaz performed best at a 6-inch row spacing while Gustoe, Aldura, Klasic, and WestBred 911 performed best at a 12-inch row spacing. Caution must be exercised when interpreting variety trials planted in 12-inch rows anti, in addition, conducted under growing conditions different from commercial practice.

This experiment was conducted to quantify herbicide carry -over effects on wheat, after plowing the cotton down with conventional and reduced tillage systems. Cotton layby applications of cyanizine, diuron, and prometryne at 1.5 lbs/Ac active ingredient did not result in wheat yields that were significantly different from the untreated checks within any of the tillage systems.

Small grain varieties are evaluated each year by University of Arizona personnel at one or more locations. The purpose of these tests is to characterize varieties in terms in terms of yield and other attributes. Variety performance varies greatly from year to year and several site years are necessary to adequate characterize the yield potential of a variety. The results contained in this report will be combined with results from previous years in a summary available from Arizona Cooperative Extension.