تقييم أداء ستة أصناف من قطن الابلند وتقدير بعض المعالم الوراثية بتأثير مواعيد الزراعة ومكافحة الادغال

Performance Evaluation of Six cotton cultivars, and estimating some genetic parameters under the influence of planting dates and weed control

Abstract
A field experiment was carried out in the field of Ibn Al-Bitar Preparatory Vocational School in Al-Hussainiya District – Kerbala Governorate during summer season 2020. A split- split plot arrangement within Randomized Complete Block Design (RCBD) with three replication was used. The objective of this experiment was to investigate the response of six cotton cultivars were assigned in the sub – sub plots (Marsumi, Lashata, Abu Ghraib, Dise, Coker310 and W888), to three weed control ( weedy check , Terifluralin 44%was sprayed at rate of 2.4 liters ha-1,and weed free) were assigned in the sub plots and planting dates (24/3 and 14/4/2020), were assigned in the main plots . The results of the experiment revealed the following for sixteen studied traits
The best significant interaction between the planting date and weed control and cultivars was achieved through the planting date 24/3 in the treatment of mechanical weed free of the cultivar Lashata for the characteristics of the seed cotton yield, the percentage of ginning outturn, number of days from planting to beginning of flowering and number of days from planting to maturity with averages reached (2073.30 kg.ha-1, 35.20%, 48.84 days and 114.16 days) respectively, and Also, planting date 24/3 in the treatment of trifluralin (44%) with the cultivar Lashata gave significant superiority for the characteristic of cotton lint yield, lint index, seed coefficient, number of open bolls and boll weight With averages of (689.9 kg.ha-1, 5.76 gm, 10.08 gm, 36.84 gm nut-1 and 5.30 gm), respectively.
The heritability is high for all the studied traits for all control treatments for the two planting dates, except for the fineness, in which the heritability for the herbicide control treatment on the planting date 24/3 and the herbicide control and weed free treatment for the agricultural date 14/4 was medium, While the characteristic of the number of seeds per boll, the heritability ratio was low for the herbicide control treatment for the seeding date 24/3 and medium for the herbicide control treatment for the planting date 14/4.
The values ​​of phenotypic variances were higher than genotypic variances for all studied traits under different control treatments for the planting date 24/3 and the planting date 14/4.
The highest positive genotypic correlation was achieved between the seed cotton yield with the lint index for the planting date 24/3 and for all control treatments, and the highest positive and genotypic correlation for the planting date 14/4 was achieved between the seed cotton yield with the number of days from planting until maturity begins for the weedy check treatment and lint length for herbicide and boll wight for weed free so they can be used as selected criterion .