] Role of Selection and Irrigation Periods in Improving Some Sunflower Characteristics Related With Drought Tolerance

Abstract

A field experiment was carried out at University of Baghdad -College of Agricultural Engineering Sciences in order to improve the drought tolerance characteristics of Sunflower using the two varieties, Shamos and Local, according to selection criteria; early flowering, low plant height and disk diameter under 10% selection intensity and three irrigation periods (5days, 8days, 10days). A split-plot according to Randomized complete block design was used with three replicates during the spring season of 2019 and 2020. Results revealed that the selection has significantly increased the yield characteristics and the drought stress tolerance; the selected genotype (LD) gave the highest peroxidase enzyme activity 20,708, it also gave the highest stability index of yield reached (79.9). Moreover, Drought stress has significantly increased the enzymes activity in the selected genotypes; the genotype (LD) gave the highest value for the POD enzyme under the irrigation of 10 days reached 26.703 mg -1 . Protein, and the selected genotype (SHS) gave the highest value of SOD enzyme under the drought stress reached 9,093 ml -1 , while the selected genotype (LF) gave the highest value of the CAT enzyme under the 10 day irrigation period reached (25,320) mlg -1 . Protein. The genetic, and phenotypic heterogeneity values did not significantly differ in relative water content and POD enzyme reached (11.95), (11.98), (24.33) and (24.66). The plant's yield varied for the selected genotypes; the genotypes (LD) and (SHD) gave the highest values of plant yield reached (8,240) and (7.341), respectively. While the selected genotype (SHF) gave the highest stress tolerance index reached 0.675. Results also revealed that the five-day irrigation treatment gave the most significant values of all the studied traits, which is not significantly differ from the eight-day irrigation treatment, especially in plant yield. Accordingly, the two varieties, Shamos and Local revealed a high response to selection, and that selection has improved most of the traits and increased the crop's stress tolerance.

The Effect of Nano and Metallic Boron Spray on some Growth Traits of Sweet Corn under Water Stress Conditions

“…This, in turn, negatively affected dry matter accumulation (Table 6) and its reduction, and hence the decrease in crop growth rate (Table 7). These results are consistent with those of [30,31,20,28,21,32,33) , who found that water stress causes a reduction in dry weight and hence a decrease in the growth rate of corn plants.…”

Genetic Parameters and Heritability of Sunflower Genotypes as Influenced by Different Nitrogen Rates

“…Traditionally, sunflower is spring crop but can also be grown in the fall season. In Iraq, it is the second important oil crop after maize and grown of area (22 thousand hectors), and yield about 17 thousand tones [1]. The oil production is the most economically important traits and the focus of many sunflower breeding methods.…”