ارزیابی عملکرد، اجزای عملکرد و سازگاری ژنوتیپ‌های امیدبخش پنبه در کشت تاخیری

به منظور ارزیابی ویژگی‌های زراعی و سازگاری ژنوتیپ‎های امیدبخش و جدید پنبه (gktb-113، skt133، sksh249، bc244، khorshid ,skn2739,nsk847 و kashmar) همراه با دو رقم زودرس (خورشید و کاشمر) و دو رقم نسبتاً دیررس (ورامین و ساحل)، آزمایشی در قالب طرح بلوکهای کامل تصادفی با سه تکرار و در طی سه سال در منطقه گرمسار انجام شد. کشت آزمایشات در 4 تا 10 خرداد صورت پذیرفت و صفات عملکرد، شاخص زودرسی، تعداد غوزه، وزن غوزه، تعداد و طول شاخه‏های زایا و رویا، تعداد گره، ارتفاع بوته و نسبت ارتفاع به گره (hnr) در سطح اندازه‌گیری شد. بر اساس نتایج تجزیه واریانس، اثر سال بر تمام صفات (به جز طول زایا و تعداد غوزه) و اثر متقابل سال × واریته بر تمام صفات (به جز ارتفاع و نسبت ارتفاع به گره) و اثر واریته بر تمام صفات مورفولوژیک، عملکرد و اجزای عملکرد (به جز hnr) معنی‌دار بود که دلالت بر تنوع قابل ملاحظه صفات در ارقام مورد مطالعه داشت. رقم bc244 از لحاظ تعداد شاخه رویا، ارتفاع و تعداد گره، رقم‌های skt133 و ورامین از لحاظ تعداد شاخه زایا و پوشش گیاهی و رقم gktb113 از لحاظ عملکرد و اجزای عملکرد در گروه نخست قرار گرفتند. تعداد غوزه، طول شاخه‌های رویا و زایا و hnr دارای همبستگی مثبت و معنی‌دار با عملکرد وش بودند در خوشه‌بندی بر اساس روش وارد و با داده‌های استاندارد شده، ژنوتیپ‌ها در سه گروه قرار گرفتند.ارقام جدید خورشید و کاشمر از لحاظ زودرسی نسبت به سایر واریت هها برتری داشتند. بر اساس نتایج این پژوهش، ژنوتیپ های امید بخش gktb113، kashmar و khorshid ضمن برخورداری از زودرسی، عملکرد و پایداری عملکرد، به ترتیب به عنوان گزینه های جدید جهت معرفی در کشت های دوم (پس از برداشت غلات) شناسایی و معرفی می شوند.

evaluation of yield, yield components and adaptability of promising cotton genotypes for late sowing dates

introductioncotton (g.hirsutum l.) is an important cash crop in iran, which plays a vital role in the economy of the country. the yield of cotton cultivars depends on their genotypic performance and adaptability. the most significant objectives of cotton variety improvement for dry agro systems include high yield, fair stability, better fiber quality and also special importance are given on suitability of different maturity groups for early, mid and late planting dates. a variety or genotype is considered to be the most adaptive or stable one if it has a high mean yield but a low degree of fluctuation over diverse environments (said, 2016; mudata et al., 2017). the association among yield related traits play a significant role toward improvement and to produce promising genotypes with high yield and quality (nawaz et al, 2019). low economic outcome of cotton due to low yields is one of the reasons for diminishing cotton production areas. to increase cotton economic profitability, it is necessary to first determine what critical farm management factors pose limitation to cotton production and then devise suitable plans to address these limitations. variety selection is an example of these limitations. cotton planting in garmsar region begins from mid-april and continues to mid-june which lasts a span of 60 days. evidently, the responses of cultivars to climatic conditions at each planting date are different. in spite of accomplished efforts, the majority of corn cultivation areas are still limited to varamin and khordad cultivars. the present research was carried out to select the best adaptable cotton variety among ten promising new genotypes for yield improvement in second planting in the dry and warm region of garmsar.materials and methods: this experiment was conducted in a rcbd experimental design with three replications under garmsar climatic condition for three years (2014, 2015 and 2016). in this study, 10 cotton genotypes including advanced hybrids and new commercial varieties were planted in may11th, 4th and 10th in the years 2014, 2015 and 2016 respectively. the studied genotypes were: gktb-113, kashmar, khorshid, skt133, sksh249, bc244, skn2739, nsk847, sahel and varamin.results: the combined analysis of three years of the study showed that the genotype bc244 produced the highest number of monopodial branches. also, the number of nodes and plant height of this genotype was higher than the others. genotype skt133 was superior to others in number of sympodial branches and was placed in same statistical group as varamin in terms of vegetative traits. seed yield, mean of boll weight and boll number in the genotype gktb113 were the highest among the all genotypes. plant height and height to node ratio of this genotype was similar to varamin and sahel, which placed it in the same statistical group. the genotypes were classified into three groups based on ward’s method of clustering for all the investigated traits. because of climatic and management conditions, early maturing is not the priority for some farmers in the region. therefore, the genotype gktb113 with producing the highest yield was found to be superior and adaptable to garmsar conditions.conclusion: results displayed considerable differences among hopeful cotton genotypes for the studied characters. boll number plant-1 and boll weight were found as major yield components to have positive correlation with seed cotton yield. however, plant height was noticed negatively correlated with yield. due to the higher yield and good vegetative characteristics of gktb113, its introduction as a new variety will expand cotton farmer’s variety choice options. for late cropping, genotypes gktb113, khorshid and kashmar are recommendable (respectively) because of their proportional earliness, seed cotton yield and yield stability.keywords: correlation, cotton, morphology, reproductive growth, vegetative growth. referencesnawaz, b., naeem, m., malik, t.a., muhae-ud-din, g., ahmad, q., and sattar, s. 2019. estimation of gene action, heritability and pattern of association among different yield related traits in upland cotton. international journal of innovative approaches in agricultural research, 3(1): 25–52.mudada, n., chitamba, j., macheke, t.o. and manjeru, p. 2017. genotype × environmental interaction on seed cotton yield and yield components. open access library journal, 04: 1–22.said, s.r.n. 2016. stability of yield and yield components for some egyptian cotton genotypes. egyptian journal plant breeding, 20: 541–552.