Estimation of Selection Indexes and some Genetic Parameters in the Genotypes of the Rice Crop Oryza sativa L.

Abstract

The current slowdown in production is a cause for concern and must be reversed to meet the population increase. Therefore, it is necessary to exploit genetic resources in maximizing production to ensure food security, as genetic differences provide a continuous source of variation, which is the basis for selecting plants that are excelled in their productive traits. A field experiment was conducted at the rice research station in Al-Mishkhab which locoted in the south of centre of Najaf provainc/ Iraq, during the summer season 2021. The 22 genotypes were cultivated, using the RCBD randomized complete block design with three replicates, and the averages were tested by Duncan’s test at a probability level of 0.05. The results of the mean squares of the genotypes were significant for all studied traits at a probability level of 1% and the highest value of an indicator as a Selection Index was (1963.052) for the genotype of IPA1. The genotype IPA1 gave the highest averages in plant height, flag leaf area, number of days to physiological maturity, grain yield and biological yield, 134 cm, 38.59 cm, 151.33 days and 10.81 tons. ha−1 and 41.77 tons.ha−1 respectively. The genotype was significantly excelled by giving the highest values of chloropyll content 44.55 SPAD for Khazar and weight of 1000 grains 28.27 g for Al Baraka genotype. The genetic and phenotypic variations were significant for all traits with the close of genetic variances values to the values of the phenotypic variances. The results of the genetic analysis showed that the values of the phenotypic and genetic variation coefficients ranged between low and medium for most traits. The percentage of heritability in the broad sense was high for all traits, and the values of the expected genetic improvement ranged between low, medium and high for the traits and the highest value of the expected genetic advance as a percentage was 44.42 for the percentage of infertility.