دانلود ترجمه مقاله شیوه های استاندارد برای اصلاح گندم مقاوم به جوانه زنی قبل از برداشت – نشریه اسپرینگر

فهرست مطالب:

 چکیده
مقدمه
روش های انتخاب مقاومت جوانه زنی قبل از برداشت در مرکز تحقیقات غلات
عدد نزولی هگبرگ و ثبت رقم
نشان گر های مولکولی DNA
نتیجه گیری

بخشی از ترجمه:

ارقام با سطوح بالا تا متوسط مقاومت به جوانه زنی قبل از برداشت بر اساس خواب RL4137 در کلاس بازاری CWRSمنتشر شده اند . اگر چه ارقام سفید بذر بر اساس خواب مشتق از RL4137  با استفاده از مکانیسم خواب مستقل از رنگ بذر منتشر شده اند ارقام واریته های سفید بذر Snowbird و Snowstar دارای سطوح بالای مقاوت PHS در مقایسه با برخی ارقام با رنگ بذر قرمز بوده اند. روش های فیلترینگ به طور کلی امکان انتخاب با سطوح بالای مقاومت PHS را بدون کاهش معنا دار در واریانس جمعیت برای صفات مهم دیگر می دهد. تولید ژن های جدید از ژن ئلاسم های غیر سازگار برای صفات مطلوب زراعی نظیر عملکرد دانه ی بالا و مقاومت به بیماری نظیر پوزاریم موجب شده است تا سطوح CWRS و  CWHWS و CWAD سطوح بالای مقاومت به PHS را داشته باشند این یک چالش فزاینده برای شناسایی نشانگر های مولکولی از نظر مقاومت به جوانه زنی قبل از برداشت است که در برنامه های اصلاح قابل کاربرد بوده و مستلزم وجود نشانگر های خوب و با تنوع بالای ژنتیکی کم هزینه و قابل انتقال به ازمایش گاه های مختلف می باشند.

بخشی از مقاله انگلیسی:

Introduction Germination of wheat (Triticum spp.) kernels, including initiation of germination and the induction of alpha-amylase without any visible evidence of embryo growth, causes significant economic losses in grain yield, grain functionality and viability of seed for planting (Derera 1989). In Canada, losses amounting to several hundred millions of dollars are experienced due to reduction in market grade in about three out of ten years (Derera 1989; Clarke et al. 2005). Economic losses due to preharvest sprouting (PHS) can be reduced by developing cultivars with increased R. M. DePauw (&) R. E. Knox A. K. Singh Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada, P. O. Box 1030, Swift Current, SK S9H 3X2, Canada e-mail: ron.depauw@agr.gc.ca S. L. Fox D. G. Humphreys Cereal Research Centre, Agriculture and Agri-Food Canada, 195 Dafoe Rd, Winnipeg, MB R3T 2M9, Canada P. Hucl Crop Development Centre, Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada 123 Euphytica (2012) 188:7–14 DOI 10.1007/s10681-011-0611-y dormancy and preharvest sprouting resistance (Czarnecki et al. 1986; McCaig and DePauw 1992) and by direct harvesting procedures (Clarke et al. 1984). Procedures used to study and or incorporate genetic resistance differ by science project objectives and by breeding objectives. Various methods have been developed to measure seed dormancy and to assess preharvest sprouting tolerance (Derera 1989). DePauw and McCaig (1991) compared various assays that measure sprouting tolerance, seed dormancy, and alpha-amylase activity. The phenotypic correlations among the various assays were significant and positive. Genotypic effects accounted for 44–90% of the phenotypic variation. Heritability expressed on a genotype mean basis ranged from 0.59 to 0.93 and was highly significant. In genetic analyses and cultivar development procedures, it is important to measure a trait such that it minimizes the error variation relative to the genetic variation. Because preharvest sprouting tolerance is only one trait of a very large suite of traits to be integrated into a cultivar, the methods used in cultivar development have to be moderately to highly heritable, reliable and yet low cost, especially in the early generations. Canadian wheat is segregated into market classes based on end-use suitability parameters of grain protein concentration, gluten strength, and kernel color (DePauw and Hunt 2001) (Table 1). Producers choose to grow cultivars of a market class based on economic considerations, market opportunities, and cultivar response to local abiotic and biotic stresses. Breeding programs target release of cultivars to meet the agronomic performance, resistance to biotic factors, and the necessary quality attributes that define each market class. This paper reviews the breeding methods employed by Canadian breeders to incorporated genetic resistance to preharvest sprouting in various wheat market classes. This information can serve as a guide to future Canadian breeders and to breeders establishing programs in other nations. Methods for selection of preharvest sprouting resistance used at Cereal Research Centre The methods used to incorporate PHS resistance, at Cereal Research Centre Agriculture and Agri-Food Canada, Winnipeg, to meet cultivar registration requirements are similar for the Canada Western Red Spring (CWRS) and Canada Western Hard White Spring (CWHWS) market classes. Crosses aim to include at least one parent that has a high level of PHS resistance (i.e. AC Domain, AC Majestic, Harvest, Snowbird, Snowstar or derivative genotype Table 2). All of these parents are derivatives of RL4137 which has a proven high level of dormancy (DePauw et al. 2009). DePauw and McCaig (1983) provided evidence that RL4137 has two mechanisms for dormancy: one associated with red seed coat color and another mechanism independent of seed coat color. For crosses with parentage that suggests PHS resistance is likely inadequate, F2 spikes are selected without stratification for maturity and stored at -20C until phenotyping. The F2 spikes are subjected to a wetting treatment in a rain simulator and only those spikes with no sprouted seeds are selected, threshed, and kernels examined. The F2 spike-F3 progeny are grown out in greenhouses over the winter months so that thorough screening is conducted and not rushed to make contra-season nursery seeding dates. Per population, 400 to 500 F2 spikes (Table 3) are exposed to 3–5 days of artificial weathering. Spikes are rated for evidence of visible germination: spikes with more than two seeds germinated (visible coleoptile or roots) are discarded. The remaining spikes are dried, threshed, and seed rated for appearance: seed rated ‘‘good’’ generally has no visible sprouting; ‘‘fair’’ seed is somewhat shriveled with little or no visible sprouting; ‘‘poor’’ seed is shriveled with many seeds sprouted. Seed shriveling may be due to seed pathogens which may have a tendency to reduce dormancy (Fox et al. 2003). The CWRS cultivars AC Majestic, AC Domain and Harvest all derive from F2 populations that were subjected to artificial weathering and have parentage related to RL4137 (Table 2). Stage two testing involves collection of spikes from single row plots 5 m long of F9 and F10 lines, and entries into pre-registration and registration trials. Stratification for maturity is achieved by sampling spikes from a plot when the majority of the ultimate stem nodes have turned brown and collapsed. Spikes are air dried for 2 days prior to storage at -20C until phenotyping. All lines are evaluated for sprouting Table 2 Examples of cultivars with preharvest sprouting resistance, parentage, and market class Name Parentage Classa Reference Source PHS Columbus Neepawa*6/RL4137 CWRS Campbell and Czarnecki 1981 RL4137_derivative AC Domain ND499/RL4137//ND585 CWRS Townley-Smith and Czarnecki 2008 RL4137_derivative Pasqua BW63*2/Columbus CWRS Townley-Smith et al. 1993 RL4137_derivative AC Vista HY344/Losprout ‘S’//HY358*3/Bt10 CPS_white DePauw et al. 1998 W_RL4137b AC Majesticc Columbus*2//Saric 70/Neepawa/3/Columbus*5// Saric 70/Neepawa CWRS Townley-Smith and Czarnecki 1995 RL4137_derivative Waskada AC_Domain*2/Sumai_3//2*Superb (Superb = Grandin*2/AC Domain) CWRS Fox et al. 2009 RL4137_derivative Harvest AC Domain*2/ND 640 CWRS Fox et al. 2010 RL4137_derivative Snowbird RL4137*6//Thatcher/Poso48/3/AC Domain CWHWS Humphreys et al. 2007 W_RL4137b Snowstar 94B46*G22/McKenzie CWHWS DePauw et al.

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