Background and objective: Investigation on genetic variability and correlation study between yield and its components of genotypes on rice may increase the opportunity to exploit its potential which will help meet the demand of high grain yield and nutrition supply. The current study aimed to determine correlation and path coefficients between twenty-two Egyptian and exotic rice genotypes to establish selection criteria which might help to develop genotypes for high yielding. Materials and methods: Twenty-two Egyptian and exotic rice genotypes were evaluated through seven agronomic traits. Agronomic data were collected during the two successive rice growing seasons, 2017 and 2018. The matrix of phenotypic correlations was estimated and analyzed into direct and indirect effects through path coefficient analysis. Results: Results showed that grain yield per plant had a high positive and significant correlation (p ≤ 0.01) with panicle number per plant, full grain number per panicle, and 1000 grain weight, 0.791**, 0.670**, and0.766**, respectively. As expected, there was a negative correlation (p ≤ 0.05) between days to heading and panicle number per plant (r =-0.496*) and with1000 grain weight (r =-0.433*). Path coefficient analysis showed that despite high positive and significant correlation (p ≤ 0.01) between grain yield per plant and many variables, a small number of these correlations was verified to have a relationship of cause and effect. Variables with positive and significant correlation and with a high direct effect on grain yield per plant were 1000 grain weight (0.5107 direct effects) followed by panicle number per plant (0.4003), and full grain number per panicle (0.3028). Conclusion: The three traits (1000 grain weight, panicle number per plant, and full grain number per panicle) are the most important variables for use in grain yield per plant assessment programs as selection indices because they have positive and significant correlations and direct and/or indirect effect on the correlation value of the increased rice grain yield production. Hence, for increasing grain yield, the direct selection of genotypes based on positively correlated traits will be more fruitful while planning any rice breeding program to achieve higher grain yield in rice.

Ancient wheats are progressively more considered as valuable resources for genes of interest especially in organic and health food markets which could be introduced into cultivated varieties. Better evaluation of primitive wheats that symbolize a valuable genetic resource may provide breeders with important sources for biotic and abiotic stress tolerance. Emmer wheat (Triticum turgidum subsp. dicoccum) is one of the most ancient of cultivated cereals, makes good bread, higher in fiber than common wheat, emmer is used is for making pasta and bread, with no need at all to use pesticides during growing season, grow in severe environments and minor lands, resistance to Septroria leaf blotch and resistance to Russian wheat aphid and Green bug. Persian wheat (Triticum turgidum ssp. carthlicum) described with many favorable characters, like being a good resistant species to stem rust and powdery mildew, plants have more tillers with good productivity, low temperature tolerant and pre-harvest budding and fairly resistant to fungus diseases. Polish wheat (Triticum turgidum subsp. polonicum) were used for bread making as many forms having grains with high protein content (27%), and it is a great source for high yielding wheat varieties characterized by plump grain, and could be used in genetic bio-fortification of durum wheat and common wheat. Lack of scientific researches and facilities to produce and marketing, in addition to concentrating on new varieties are considered as limitation factors of expanding these species. For better adaptation to climate change and for future food security, it is highly recommended to improve utilization and sustainable use of targeted species and cooperation between scientists and researcher on the national and international levels. This review is an attempt to highlight the value of targeted species with general information about classification, origin and distribution, importance domestication, characterization and conservation, traditional breeding and role of each of molecular biology, tissue culture and mutation in exploiting genetic variation in targeted species.

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Seven wheat genotypes (Triticum dicoccum) and the local check sham5 were planted all at Al-Ghab and Izra Research centers in The General Commission for Scientific Agricultural Research in Syria during growing season 2010/2011. Yield components (number of total and fertile tillers per plant, number and weight of grains per spike, weight of thousand grain and individual plant grain yield) were studied in two sites in order to predict their effect and to determine their effects on grain yield in order to define selection criteria for grain yield. Results revealed all studied traits except total tillers number were positively correlated with grain yield, and only (fertile tillers number and grain number per spike and grain weight per spike) had a significant regression with grain yield and these traits can explain about (27.6, 67.7, 62.2)% respectively of the variation final grain yield. Results of path analysis indicated that the direct effect of fertile tillers per plant and grain weight per spike on grain yield was positive and high (0.6178, 0.7563) respectively, so that we can depend on them in breeding program as selection criteria to increase grain yield in plant.

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