پديد آورندگان :
فلاح، الهيار سازمان تحقيقات، آموزش و ترويج كشاورزي - موسسه تحقيقات برنج كشور , باقري، ليلا پژوهشگاه علوم و فنون هسته اي - پژوهشكده كشاورزي هسته اي , نبي پور، عليرضا سازمان تحقيقات، آموزش و ترويج كشاورزي - موسسه تحقيقات برنج كشور
كليدواژه :
اجزاي عملكرد , تجزيه خوش هاي , اشعه گاما , موتاسيون القايي , موتانت برنج
چكيده فارسي :
توليد ارقام زراعي مناسب براي كاشت در اراضي شاليزاري، به بررسي ذخاير ژنتيكي و شناسايي مواد گياهي برتر وابسته است. به منظور بررسي صفات زراعي و عملكرد در 133 موتانت نسل چهارم حاصل از پرتوتابي سه رقم طارم محلي، حسني و عنبربو، نشاهاي اين موتانت‌ها به همراه والدين به صورت طرح بلوك‌هاي حجيم شده (آگمنتد) با 6 بلوك در مزرعه كاشته شدند. براي هر موتانت و شاهد، صفات تعداد روز تا 50% گلدهي، ارتفاع بوته، تعداد پنجه بارور، عملكرد و اجزاي عملكرد اندازه‌گيري شد. نتايج نشان داد كه موتاسيون باعث بروز تنوع معني‌دار در تمام صفات مورد مطالعه شده است. تجزيه خوشه‌ايِ موتانت‌هاي حاصل از طارم محلي، حسني و عنبربو، آن‌ها را به ترتيب به 5، 3 و 4 گروه تقسيم‌بندي كرد. بررسي ميانگين صفات نشان داد كه موتانت‌ها بطور ميانگين نسبت به شاهدها زودرس‌تر بودند. همچنين، موتانت‌ها، نسبت به شاهد مربوطه بين 10 تا 30 درصد كاهش ارتفاع نشان دادند. هرچند از نظر صفت عملكرد تنوع معني‌داري بين موتانت‌ها ديده شد، ولي در بيشتر موارد، عملكرد موتانت‌ها مشابه با شاهد بود. افزايش عملكرد موتانت‌هاي انتخابي نسبت به شاهد بين 10 تا 27 درصد بود. در نتيجه آزمايش اخير، 8 لاين با عملكرد بيشتر نسبت به شاهدها و 12 لاين زودرس و پاكوتاه با عملكرد مشابه شاهد براي مطالعات بعدي انتخاب شدند.
چكيده لاتين :
Introduction: Diversity and selection are the two fundamental components of every plant breeding program and the success of any such projects hinges on the existence of ample trait diversity and clear objectives (Kiani and Nematzadeh, 2013). Mutation can play a pivotal role in plant breeding and evolution by creating more genetic diversity (Esfahani and Fotokian, 2003). Ionizing radiations such as gamma rays with mutagenic effects are able to generate more varied plant gene pool. Therefore, they can be used as complementary tools for plant breeding processes (Bagheri et al., 2014). Development of improved rice varieties for paddy fields relies on the assessment of genetic resources and the selection of the superior plant material (Kiani and Nematzadeh, 2013). One of the best methods for improving high quality but low yielding local rice varieties, which are highly appreciated by customers, would be mutation breeding, as it changes only rather small parts of genome and there are high chances that the good quality of these varieties would remain intact (Majad et al., 2003). Gamma irradiation has been reported to be highly successful in rice breeding (Wani and Anis, 2008). The aim of this study was to use mutation breeding for yield and stand structure improvement in local rice varieties without any decline in their quality through the selection of the superior rice lines from the fourth generation mutant and yield comparison of the mutants with their parental counterparts on field experiments. Material and methods: To obtain suitable lines for paddy fields, the seeds of local rice varieties of Tarom Mahalli, Hasani and Anbarboo were first subjected to gamma rays at dose rates of 100, 200, 250, 300 and 350 Gary using gammacell irradiator at the Karaj Nuclear Research Center in the year 2010. The irradiation doses were determined as the appropriate quantities following the seed germination tests and the measurement of seedling growth attributes and the survival rate of the seeds. The line selection of the varieties in the second generation mutants (M2) was done on the basis of maturity earliness, panicle morphology, plant height, grain yield per hill, and their relative tolerance to pests and diseases. The seeds derived from the selected M3 mutants consisted of Tarom Mahalli (66 genotypres), Hassani (38 genotypes) and Anbaroo (29 genotypes) which were sown along with their parental counterparts at the nursery bed of the Rice Research Institute of Mazandaran (Amol), Iran in 2014. The seedlings were tended in the nursery for one month. Then, they were transplanted into paddy field trials. The experiment was laid out in an augmented design with 6 blocks. The parental counterparts as check treatment were randomly assigned to the blocks. Each M4 mutant occurred only once per block. Measurements were made on days to 50% flowering, plant height, number of panicles per hill, yield and yield components. Analysis of variance for check treatments was performed based on completely randomized block design model using SAS statistical software. The mean comparison was done by LSD (Least Significant Difference) test. To compare the means obtained from mutant lines, the standard deviation was computed using the formula Sd=√MSE(2c+1)/c, where MSE represents the average squared error for the check varieties for the each measured trait and C represents the number of check treatments. To classify the M4 mutants derived from their respective parental varieties (the check treatments), cluster analysis was conducted on the basis of the measured traits by Ward`s method using SPSS (ver.16) software. Results &Discussion: Results showed that mutation produced significant genetic diversity in the mutants for all of the studied traits. Cluster analysis divided the mutants from Tarom Mahalli, Hasani and Anbarboo varieties into 5, 3 and 4 groups, respectively. On average, the mutants were earlier than their respective parents and had a shorter plant height. Although most of the mutants had a yield similar to their parents, the selected mutants had yields 10 to 27% higher than their respective check. The improvement in yield was attributed to the higher number of grains per panicle. Based on the results, eight lines with high yield, and 12 lines with same yield as checks but with early maturity and short plant stature were selected. Wani and Anis (2008) reported that improvements in morphological traits such as number of grains per pod and number of pods were the main reasons for the higher performance of three gamma-induced pea mutant lines. Esfahani and Fotokian (2003) found a rice mutant line from Domsiah local variety which was 15 days earlier than the original variety. Zenalinajad et al. (2003), using cluster analysis based on morphological traits, divided their 100 rice genotypes into four groups. Conclusion: Days to 50% flowering of Hasani and Tarom mahali were 95 days, while in Anbarboo variety it was 108 days. The yield of Hasani variety was lower than the other varieties. The range of plant height in the mutants was between 100-135 cm. Only one mutant of Anbarboo had163 grains per panicle, which was significantly higher than the other Anbarboo mutants. The genetic gain of yield in mutants was between 11 to 17 percent over Anbarboo check. 20 Mutant lines were selected based on higher yield than checks and shorter growth duration, and most of them were from groups 3 and 4. They had lower height and more filled grains per panicles than the check varieties.
