Abstract
Grain characteristics, particularly grain weight, grain morphology, and grain protein content (GPC), are important components of grain yield and quality in wheat. A set of 98 bread wheat landraces from different geographic regions of Iran were used across 2013-2014 and 2014-2015 to determine the phenotypic diversity and relations between thousand grain weight (TGW), grain morphology and grain quality. A high-throughput method was used to capture grain size and shape. The genotypes were significantly different (P < 0.001) for all traits which reflects the high levels of diversity. A moderate to high broad sense heritability was found for all traits and ranged between 0.68 and 0.95 for grain yield and factor from density (FFD), respectively. Significant positive correlations were observed between TGW and grain size (or shape) exception of aspect ratio (AR) and roundness. However, grain quality traits, especially GPC had significant negative correlation with TGW. Based on stepwise regression analysis by taking TGW as dependent variable, grain volume, FFD, width, perimeter and Hardness Index (HI) were recognized as the most important traits and explained more than 99.3% of total variation of TGW. The path analysis revealed that FFD has maximum direct effect on TGW followed by volume, whereas perimeter and width had relatively less direct effect on TGW. According to cluster analysis, landraces separated into 5 clusters, and cluster III and IV had the maximum and minimum average for the most traits, respectively. Our study provides new knowledge on the relations between TGW, grain morphology and grain quality in bread wheat, which may aid the improvement of wheat grain weight trait in further research.
Highlights
Wheat (Triticum aestivum L.) as a strategic crop has a vital role in the developing countries economy and known as main food crop in abiotic stress prone areas which have low output productivity such as Iran (Abdipour et al, 2013)
In the past four decades, improvement of grain yield has come from increased grains per square meter or larger grain sizes, due to the utilization of Rht genes in wheat breeding (Calderini and Reynolds, 2000)
It has been proven that grain yield is a complex and quantitative trait that controlled by a number of genes with low heritability and it is significantly influenced by the environment, which make it difficult to be manipulated and improved in breeding programs (Koebner and Snape, 1999; Deng et al, 2011)
Summary
Wheat (Triticum aestivum L.) as a strategic crop has a vital role in the developing countries economy and known as main food crop in abiotic stress prone areas which have low output productivity such as Iran (Abdipour et al, 2013). It is a huge challenge to ensure global food security through sustainable wheat production for the projected population with the increasing adverse impact of climate change (Palm et al, 2010). In the past four decades, improvement of grain yield has come from increased grains per square meter or larger grain sizes, due to the utilization of Rht genes in wheat breeding (Calderini and Reynolds, 2000). It has been proven that grain yield is a complex and quantitative trait that controlled by a number of genes with low heritability and it is significantly influenced by the environment, which make it difficult to be manipulated and improved in breeding programs (Koebner and Snape, 1999; Deng et al, 2011). According to low heritability for most of the yield-related traits (Shi et al, 2009), and laborious, time-consuming, and costly to measure yieldrelated traits, assess all of them at the early stages of a breeding
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
