برآورد تركيب‌پذيري و هتروزيس براي صفات آگرومورفولوژيك سيب‌زميني (Solanum tuberosum L) با استفاده از تجزيه لاين × تستر

Combining Ability and Heterosis for Some Agro-Morphological Traits in Potato (Solanum tuberosum L.) Using Line × Tester Mating Design

به‌ منظور مطالعه تركيب‌پذيري و هتروزيس عملكرد غده و تعدادي از صفات زراعي در سيب‌زميني، شش هيبريد حاصل از تلاقي سه لاين با دو تستر به همراه والدين به روش لاين ×تستر (2× 3) و در قالب طرح بلوك‌هاي كامل تصادفي با سه تكرار در سال زراعي 1393-1394 در مركز تحقيقات كشاورزي اردبيل مورد ارزيابي قرار گرفتند. اختلافمعني‌داربين ژنوتيپ‌ها از لحاظ كليه صفات مورد مطالعه امكان تجزيه‌ و تحليل ژنتيكي برمبناي روش لاين ×تستر ميسر كرد. بر اساس نتايج تركيب‌پذيري عمومي لا ين‌ها و تسترها،لاين (L1 (Caeser داراي تركيب‌پذيري عمومي مثبت و معني‌دار براي عملكرد غده، وزن و تعداد غده در بوته، تعداد ساقه اصلي و ارتفاع بوته بود. همچنين تستر (T1(Luca داراي تركيب‌پذيري عمومي مثبت و معني‌دار براي عملكرد غده، وزن و تعداد غده در بوته و درصد ماده خشك غده بود. بنابراين، از اين لاين و تستر مي‌توان به‌عنوان والدين در برنامه‌هاي اصلاحي بهره گرفت. هيبريدهاي (T1× L 3) (Satina × Luca) و (T2× L1) (Caeser × Savalan) از نظر صفات عملكرد غده،وزن و تعداد غده در بوته داراي تركيب‌پذيري خصوصي مثبت و معني‌دار بودند. نسبت واريانس تركيب‌پذيري عمومي به واريانس تركيب‌پذيري خصوصي و ضريب بيكر براي تمام صفات مورد مطالعه كمتر از يك بود كه اين امر حاكي از نقش مؤثرتراثر غير افزايشي ژن‌ها در كنترل ژنتيكي صفات مورد بررسي دارد. وراثت‌پذيري عمومي بالا و وراثت‌پذيري خصوصي نسبتاً پايين براي صفات مختلف مشاهده شد. بيشترين ميزان هتروزيس براي صفت عملكرد غده متعلق به هيبريد (T1× L3) (Satina × Luca) بود.

Background and Objectives The nature and magnitude of gene action is an important factor in developing an effective breeding program. Combining ability analysis is useful in assessing the potential inbred lines and helps in identifying the nature of gene action involved in various quantitative characteristics. This information is helpful to plant breeders for formulating hybrid breeding programs. Therefore, the objectives of the present research were to determine combining ability, heritability and heterosis of tuber yield and some agronomic traits in potato using line × tester mating design. Materials and Methods In order to determine combining ability, heritability and heterosis of tuber yield and some agronomic traits in potato, three lines were crossed with two testers. Parents and their F1 progenies were arranged in randomized complete block design with three replications using line × tester (3 × 2) mating design. Results Analysis of variance showed significant differences among genotypes for all traits; thus line × tester analysis was performed. Among the lines, line L1 (Caeser) had significant positive GCA for tuber yield, tuber weight per plant, tuber number per plant, main stem number and plant height. Among the testers, tester T1 (Luca) showed significant positive GCA for tuber yield, tuber weight per plant, tuber number per plant and tuber dry matter. Among the hybrids, the hybrids (Satina × Luca) (T1 × L3) and (Caeser × Savalan) (T2 × L1) showed significant positive SCA effects for tuber yield, tuber weight per plant and tuber number per plant. The SCA variance was higher in magnitude than the GCA variance for all the characteristics and baker coefficient indicated the predominance of non-additive type of gene action for the expression of these characteristics. High general heritability and relatively low specific heritability were observed for all traits. Hybrid (Satina × Luca) had the highest heterosis for tuber yield. Discussion The importance of additive and non-additive genetic effects is well established in controlling many traits in potato. It was shown that the dominance effects of the genes played a major role in the variation of tuber yield in potato. Based on the results of the current study the SCA variance was higher in magnitude than the GCA variance for all the characteristics and baker coefficient indicated the predominance of non-additive type of gene action for the expression of these characteristics. Heterosis and combining ability is prerequisite for developing a good hybrid variety of potato. According to this research, the (Satina × Luca) cross had the highest heterosis for tuber yield and was recommended as the most promising combination for developing high yielding hybrid potato genotypes.