|SHAHID, MOHAMMAD - International Center For Biosaline Agriculture Of Dubai|
Submitted to: Emirates Journal of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2013
Publication Date: 1/1/2014
Citation: Jaradat, A.A., Shahid, M. 2014. How diverse a farmer-managed wheat landrace can be? Emirates Journal of Food and Agriculture. 26(2):93-118.
Interpretive Summary: For thousands of years, traditional wheat farmers contributed to the wealth of variation available in landraces. This improved wheat yield and adaptation in different parts of the world. We identified the variation level in a wheat landrace managed by subsistence farmers and grown under marginal wheat production environment. We suggest that farmers grow and maintain highly variable wheat landraces to lower the risk of failure under marginal production conditions and to increase food security of isolated communities. Students and professionals working in the field of genetic resource conservation and utilization will benefit from the statistical methods used in this study. The landrace populations identified in the study are valuable sources of traits for adaptation to marginal wheat-growing parts of the world with high temperature and salinity, and may have gene complexes to combat climate change.
Technical Abstract: Phenotypic variation in phenological, quantitative and qualitative traits was assessed in geographically-isolated, farmer-managed wheat landrace populations grown under subsistence farming conditions. Several multivariate, genetic diversity and sequential equation modeling procedures were used to build a comprehensive structure of the landrace and to (1) identify and construct multivariate distances between components of the landrace, (2) identify plant- and seed-related traits contributing to its composition, (3) build principal components that can account for maximum variation, (4) quantify variance components accounted for by major seed qualitative traits, (5) partition total diversity and estimate levels of population differentiation, (6) build and validate a predictive model of landrace population-trait association, (7) identify traits affecting spikelet fertility as a critical component of grain yield under the prevailing hot conditions in Oman, and (8) construct and interpret structural equation models to estimate the direct and indirect effects of quantitative and qualitative traits on grain yield per plant for each landrace population. The results will be discussed within the context of on-farm conservation and sustainable utilization of endangered wheat landrace populations under subsistence farming and to illustrate the use of advanced multivariate statistical procedures in assessing phenotypic variation in sub-divided populations of landraces.