Crop phenotyping for wheat yield and yield components against drought stress

Water deficit is a most limiting factor for wheat in rain-fed agricultural systems worldwide. The effects of drought stress on some root features and yield and yield components in wheat (Trticum aestivum L.) were carried out in a factorial experiment based on completely randomized design, under greenhouse condition. The four experimental irrigation regimes, irrigation after 75% of the water was depleted (control), irrigation after 65% of the water was depleted (mild stress), irrigation after 55% of the water was depleted (moderate stress) and irrigation after 45% of the water was depleted (severe stress) were randomized for the main plots. The subplot treatments included eight wheat genotypes. Results showed that Interaction Drought stress with Variety had significantly affected on Total Root Volume and Dry Matter, Number of Tiller and also Shoot Dry Matter. Value of Total Root Volume and Dry Matter, Shoot Dry Matter and Number of Tiller in irrigated varieties were more than rainfed in whole of Drought stresses. N-87-20 variety had most amounts of Total Root Dry Matter, Total Root Volume (exception of control) in all of stresses and control. Root properties influence on yield and other morphological traits of wheat. Stress intensification increase root growth than plant organ so that wheat root can uptake water from soil to compensate damage caused by stress

Assessing drought tolerance and regional patterns of genetic diversity among spring and winter bread wheat using simple sequence repeats and phenotypic data

This study was conducted to assess drought tolerance and regional-based patterns of diversity of bread wheat accessions and to identify new sources of diversity that could accelerate the development of improved wheat varieties better suited to meeting the challenges posed by changing climate in Southern and Eastern Europe. For this, genetic diversity assessed by simple sequence repeats (SSR) markers was compared with diversity evaluated using 19 phenotypic traits averaged over irrigated and drought-stress field conditions. Thirty-six SSR were used to profile 96 wheat genotypes from the collection of genetic resources at the Institute of Field and Vegetable Crops, Novi Sad, Serbia. A total of 46 loci and 366 alleles were detected, with a range of 3-21 alleles per locus. The polymorphic information content was estimated to be 0.61. The genetic distance for all possible 4560 pairs of genotypes ranged from 0.06 to 0.91 with an average of 0.65. Genotypes were grouped according to their drought tolerance (high, medium, low) and region of origin. Analysis of molecular variance showed that over 96% of the total variation could be explained by the variance within the drought tolerance and geographical groups. As a whole, genetic diversity among the high drought tolerance genotypes was considerably higher than that among low drought tolerance genotypes. Comparative analysis of SSR diversity among six regional groups revealed that the genotypes from North America exhibited more genetic diversity than those from other regions. Two dendrograms were constructed based on phenotypic and molecular analyses using the Unweighted Pair Group Method with Arithmetic Mean method and were found to be topologically different. Genotypes characterised as highly drought tolerant were distributed among all SSR-based cluster groups. This implied that the genetic basis of drought tolerance in these genotypes was different, thereby enabling wheat breeders to combine these diverse sources of genetic variability to improve drought tolerance in their breeding programs