ABSTRACT
High molecular weight glutenin subunits (HMW-GSs) at the Glu-1 loci play an important role in the variation of dough strength, elasticity, and end-use quality of bread wheat. Multilocation trials in a wide range of climatic conditions and crop management practices help explain the role of HMW-GSs in the rheological properties of dough. In the current study, allelic variation of HMWs and quality scores were determined in 28 bread wheat cultivars across a wide range of climates and locations in Iran. Twelve HMW-GSs subunits (3 at Glu-A1, 7 at Glu-B1 and 2 at Glu D-1) in 16 unique combinations were identified in the studied cultivars. In the most rheological properties associated with good bread-making quality, the compositions of 1/17 + 18/5 + 10, 1/13 + 16/5 + 10 and 2*/7 + 9/5 + 10 (all with a quality score of 10) had significantly higher values than the other allelic compositions. While, the lowest values were observed in 1/21 + 19/2 + 12 (quality score of 6). The degree of dough softening was significantly greater in 1/21 + 19/2 + 12 than other allelic combinations. At Glu-A1, Glu-B1 and Glu-D1, 2*, 17 + 18 and 5 + 10 had significantly greater qualitative and rheological properties than the other subunits, which are related to the good quality of wheat flour. While null at Glu-A1, subunits 21 + 19 at Glu-B1 and 2 + 12 at Glu-D1 were associated with weak baking quality. Moreover, the highest dough softening values at Glu-A1, Glu-B1 and Glu-D1 were observed in null, 21 + 19 and 2 + 12 subunits, respectively. A negative and significant correlation (P < 0.05) was observed between the degree of dough softening and other qualitative and rheological properties related to good bread-making performance. The results of this study demonstrated the role of HMW-GSs in determining the end-use quality of bread wheat across a wide range of climates and environments. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01324-6.
ABSTRACT
Olive (Olea europaea L.) is one of the most cultivated tree species in Iran. This plant is characterized by its tolerance to drought, salt, and heat stresses while being vulnerable to frost. During the last decade, periods of frost have occurred several times in Golestan Province, in the northeast of Iran, which caused severe damage to olive groves. This study aimed to evaluate and individuate autochthonous Iranian olive varieties with regard to frost tolerance and good agronomic performance. For this purpose, 218 frost-tolerant olive trees were selected from 150,000 adult olive trees (15-25 years old), following the last harsh autumn of 2016. The selected trees were reassessed at different intervals, i.e., 1, 4, and 7 months after the cold stress in field conditions. Using 19 morpho-agronomic traits, 45 individual trees with relatively stable frost-tolerance were reevaluated and selected for this research. Ten highly discriminating microsatellite markers were used for the genetic profiling of the 45 selected olive trees, and, ultimately, five genotypes with the highest tolerance among 45 selected ones were placed in a cold room at freezing temperatures for image analyses of cold damage. The results of morpho-agronomic analyses evidenced no bark splitting or symptoms of leaf drop in the 45 cold-tolerant olives (CTOs). The oil content of the cold-tolerant trees comprised almost 40% of the fruit dry weight, highlighting the potential of these varieties for oil production. Moreover, through molecular characterization, 36 unique molecular profiles were individuated among the 45 analyzed CTOs that were genetically more similar to the Mediterranean olive cultivars than the Iranian ones. The present study demonstrated the high potential of local olive varieties, which would be promising and more suitable than commercial olive varieties, with regard to the establishment of olive groves under cold climate conditions. This could be a valuable genetic resource for future breeding activities to face climate changes.
