پژوهشنامه اصلاح گیاهان زراعی (Jun 2024)
Selection of Superior Durum Wheat Lines in the Warm and Dry Northern Region of Khuzestan Province
Abstract
Extended Abstract Background: Wheat is a plant that is cultivated in different environments around the world and provides approximately 20% of the energy and 25% of the protein needs of the world population. Durum wheat (Triticum turgidum L. var durum) is an industrial product that is mainly used in the pasta production industry. In addition, the difference in the price of durum wheat in the world markets compared to bread wheat has prompted some countries to increase the area under cultivation and production of this crop and start its export to supply their bread wheat needs through imports, thereby saving large sums of foreign currency. Although it is often believed that durum wheat produces less yield than bread wheat, the results of national uniformity tests conducted in recent years have shown that not only the yield of durum wheat is not lower than that of bread wheat but also the promising lines of durum wheat has an increase in yield in the conditions of the tests. If we consider a 20% increase in the price of its grain, the development and promotion of its cultivation in tense areas can provide more economic benefits for the producers and the country. The production of crop cultivars with appropriate characteristics, high yields, and stable production is one of the main goals of wheat breeding programs. Therefore, the identification of suitable lines and cultivars for cultivation in each geographical region is of special importance. It is possible to achieve such a goal by evaluating the set of new lines of each plant in each region. According to the special program of the Seed and Plant Improvement Institute (SPII), which plans to increase the self-reliance coefficient of wheat for the introduction of new varieties, this study also aims to obtain more productive and promising durum wheat genotypes in the northern region of Khuzestan province. Methods: To identify the best durum wheat lines in terms of yield and other agricultural traits, an experiment was carried out during two 2020-2021 and 2021-2022 crop years in the research farm of Safiabad Agricultural and Natural Resources Research Center, Dezful. New durum wheat lines (n = 76) were evaluated observationally along with three control varieties Aran, Hana, and Mehregan in the first year and 37 best lines of the first year were evaluated in the form of an alpha lattice design, along with three control varieties, in the second year. In addition to seed yield, other important agricultural traits, including heading date, physiological maturity date, length of seed filling period, lodging rate, plant height, and 1000 kernel weight, were calculated and considered in the final selection. For the results of each year, statistical parameters (indices of central tendency) were measured using Excel software. The correlation between traits was measured using SPSS software. In addition, MetaR software was used to analyze the variance of the Alphalatis design. To group the tested lines, a dendrogram was drawn using the Ward method and SPSS software. Results: The results of the trait analysis in the first year showed that the tested lines had a very high variety so that their yield ranged from 5883 kg/ha for the weakest line to 8350 kg/ha for the best line, and the average yield of all tested lines was 7231 kg/ha. In addition, the average yield of 37 selected lines in the second year was about 6423 kg/ha, which was about one ton less than the yield of the same lines in the first year (7397 kg/ha). One of the main reasons for this decrease in yield can be attributed to the increase in the temperature of March in the second year (20 °C) compared to the first year (16 °C), which caused the average grain filling period from 49.3 days in the first year to reach 45.1 days in the second year. Finally, according to the total measured traits of each line during two crop years and cluster analysis, lines 6, 38, 57, 58, 59, and 73 were selected as the best lines. The yields of these lines were 8350, 8303, 7917, 7537, 8000, and 8130 kg/ha in the first year, and 6933, 6917, 6775, 7045, 7178, and 6815 kg/ha in the second year, respectively. The average yields of Aran, Hana, and Mehregan controls were 7207, 7148, and 7109 kg/ha in the first year, and 5698, 6208, and 5927 kg/ha in the second year, respectively. The dendrogram drawn using the total of the measured traits placed the 40 studied lines in three different groups, each of which had two subgroups. An important point about the cluster analysis is that the selected top lines (6, 38, 57, 58, 59, and 73) are placed in one group, and only line 61 is added to them. Conclusion: In the pedigree study of the top lines, a common parent named PLATA was found in the pedigree of the four lines, which probably made these lines superior to the other tested lines. According to these results, it is possible to propose and implement the use of this line to improve the wheat breeding program in the hot and dry areas of the south.
