پارامترهای ژنتیکی

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1 - ارزیابی پارامترهای ژنتیکی برخی از ژنوتیپ‌های گندم نان تحت تاثیر تیمار پلی اتیلن گلایکول6000 و استفاده از Gt-Bipiot
زهرا مروتی محمد نورانی

به‌منظور بررسی ارتباط فنوتیپی و ژنوتیپی میان ویژگی‌های موثر در مرحله جوانه‌زنی در شرایط تنش خشکی، 19 ژنوتیپ گندم نان در قالب طرح کاملاً تصادفی با سه تکرار در آزمایشگاه گروه زراعت و اصلاح نباتات پردیس کشاورزی و منابع طبیعی دانشگاه رازی کرمانشاه مورد ارزیابی قرار گرفت. نت أکثر

به‌منظور بررسی ارتباط فنوتیپی و ژنوتیپی میان ویژگی‌های موثر در مرحله جوانه‌زنی در شرایط تنش خشکی، 19 ژنوتیپ گندم نان در قالب طرح کاملاً تصادفی با سه تکرار در آزمایشگاه گروه زراعت و اصلاح نباتات پردیس کشاورزی و منابع طبیعی دانشگاه رازی کرمانشاه مورد ارزیابی قرار گرفت. نتایج تجزیه و تحلیل واریانس (ANOVA) نشان داد که اختلاف معنی‌داری بین ژنوتیپ‌های مورد ارزیابی از نظر صفات درصد جوانه زنی (GP)، طول کلئوپتیل (KL)، میانگین زمان جوانه زنی (MGT)، ضریب سرعت جوانه زنی (CVG)، میانگین سرعت جوانه زنی (AVG) و شاخص بنیه بذر (SV) در هر دو شرایط نرمال و تنش خشکی مشاهده شد که نشان دهنده وجود تنوع ژنتیکی قابل توجه و امکان انتخاب ژنوتیپ‌های متحمل به تنش خشکی است. بر اساس بای پلات به‌دست آمده در آزمون جوانه زنی نیز ژنوتیپ شماره 16 در گروه A قرار گرفت رابطه ژنتیکی مثبت و معنی‌داری میان صفات SV،AVG ، GP و RL مشاهده شد. که با نتایج نمودار GT-biplot مطابقت کامل داشت. وراثت پذیری و پیشرفت ژنتیکی بالا برای AVG،GP و SV مشاهده گردید که این موضوع می‌تواند حاکی از عمل افزایشی ژن‌ها باشد. بر این اساس روش اصلاحی انتخاب برای صفات مورد مطالعه در ژنوتیپ‌های مورد بررسی موثر است. به منظور دسته‌بندی ژنوتیپ‌های مورد مطالعه از تجزیه خوشه‌ای به روش Ward استفاده شد. که ژنوتیپ‌های مورد مطالعه در شرایط تنش اعمال شده و نرمال (شاهد) در سه گروه قرار گرفتند. تفاصيل المقالة

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2 - Phenotypic and Genetic Factors Affecting on Reproductive Lifetime of Lori-Bakhtiari Ewes
م. وطن خواه

In this study phenotypic and genetic factors affecting the reproductive efficiency of Lori-Bakhtiari ewes were determined using 8202 reproductive records of 2478 ewes collected at Shooli research station in the southwestern part of Iran (Shahrekord) during 1989 to 2012. أکثر

In this study phenotypic and genetic factors affecting the reproductive efficiency of Lori-Bakhtiari ewes were determined using 8202 reproductive records of 2478 ewes collected at Shooli research station in the southwestern part of Iran (Shahrekord) during 1989 to 2012. Reproductive efficiency over all consecutive lambing opportunities were calculated by adding the total reproductive efficiency traits per ewe joined for all of the parturition opportunities. Reproductive traits included in the current study were: number of parity (NP), total number of lambs born (TNLB), total number of lambs weaned (TNLW), total of lambs birth weight (TLBW), total of lambs weaning weight (TLWW), total of lambs weaning weight per kg ewe body weight (TLWW/EBW) and total of lambs weaning weight per kg metabolic ewe body weight (TLWW/MEBW). The data set analyzed with multi-trait animal model included the fixed effects of birth year of ewe, number of parturition in ewe's lifetime, ewe body weight as covariate and random effects direct additive genetic and residual. The overall mean of NP, TNLB, TNLW, TLBW, TLWW, TLWW/EBW and TLWW/MEBW were 3.31, 3.31, 3.21, 16.51 kg, 87.31 kg, 1.51 and 4.16, respectively. The effect of non-genetic factors were significant for all investigated traits in this study (P<0.01). The heritability estimates were medium (0.30) for NP and low (0.08 to 0.11) for other reproductive efficiency traits. The estimates of genetic and phenotypic correlations between the traits were high (0.72 to 0.99) or medium to high (0.57 to 0.99). Thus, improving environmental effects could make significant improvements in reproductive efficiency traits at first. The low to medium heritability estimate and high genetic correlations obtained between reproductive efficiency traits in ewe's lifetime and high phenotypic standard deviation from them indicated that improvement by selection of all of traits, especially NP can be improved TLWW as net reproductive efficiency trait in Lori-Bakhtiari ewes. تفاصيل المقالة

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3 - Response to Selection for Body Weight in Japanese Quail (<i>Coturnix coturnix japonica</i>)
اس. هوسن آ.م. عبد الرحمان ال-خدری آ.م. حسن

The present studyinvestigated the impact of selection for body weight (BW) on productive performance, predicted BW and genetic improvement of related traits in Japanese quail. Base population, selected parent and F1 progeny were tested. Pens and cages were used for rear أکثر

The present studyinvestigated the impact of selection for body weight (BW) on productive performance, predicted BW and genetic improvement of related traits in Japanese quail. Base population, selected parent and F1 progeny were tested. Pens and cages were used for rearing and breeding. A total of 240 birds in two successive generations, 27 sires and 54 dams (as selected parents) were used. Body weight from multiple regression equation, covariance analysis and combining models were estimated, response to selection, realized heritability and genetic correlation were computed for BW, weight gain (WG), feed intake (FI) and feed conversion ratio (FCR). The results showed that the response to selection for BW, WG, FI and FCR were 11.48 g, 27.04 g, 37 g and -0.2, respectively. The estimated heritabilities for the same traits were 0.78, 0.67, 0.52 and 0.77, respectively. Predicted equation (DUHOK equation) for BW as dependent variable on the initial body weight and sex ratio was derived. The final response for the body weight was determined as 5.84 % of live BW. تفاصيل المقالة

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4 - Genetic Evaluation of some Carcass Characteristics Assessed by <i>in vivo</i> Real Time Ultrasonography in Baluchi Sheep
ع. محمدی س. حسنی س. زره داران م. باقری ع. میرشاهی

In order to evaluate carcass characteristics of a nucleus flock of Baluchi sheep, in vivo ultrasound technique was used to measure backfat thickness (UBFT) and longissimus dorsi muscle area (ULMA) and also to estimate genetic parameters for these ultrasonic traits and l أکثر

In order to evaluate carcass characteristics of a nucleus flock of Baluchi sheep, in vivo ultrasound technique was used to measure backfat thickness (UBFT) and longissimus dorsi muscle area (ULMA) and also to estimate genetic parameters for these ultrasonic traits and live weights in different ages. The data were collected from 576 animals during 2011. (Co)variance components were estimated by univariate and bivariate animal models using restricted maximum likelihood and Asreml software. Females had higher UBFT and ULMA than males. Estimates of direct heritabilities were 0.32, 0.23, 0.27, 0.02, 0.12, 0.22 and 0.18 for UBFT, ULMA, birth weight (BW0), weaning weight (BW3), 6 month weight (BW6), 9 month weight (BW9) and yearling weight (BW12), respectively. There were positive and high genetic (0.68±0.15) and phenotypic (0.62±0.03) correlations between UBFT and ULMA. The genetic correlations among ultrasonic and pre 6 month weights were positive and low except for BW0 and ULMA (0.39±0.28). Contrarily, moderate to high positive genetic correlations between ultrasonic traits and weaning and post-weaning weights were found (0.33 to 0.61). Phenotypic correlations between ultrasonic and growth traits were positive and ranged from 0.09 to 0.37. High positive genetic correlation between UBFT and ULMA suggests that selection for larger muscle mass result in higher fat carcasses. تفاصيل المقالة

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5 - Genetic Analysis of Ewe Productivity Traits in Baluchi Sheep
م. جعفراوغلی ع. صفری ع.ا. شادپرور ن. قوی حسین-‌زاده

The present study was carried out to estimate (co)variance components and genetic parameters for some productivity traits of Baluchi ewes. The data were collected during a 31 year period (1984-2014) at the experimental breeding station of Baluchi sheep, which is located أکثر

The present study was carried out to estimate (co)variance components and genetic parameters for some productivity traits of Baluchi ewes. The data were collected during a 31 year period (1984-2014) at the experimental breeding station of Baluchi sheep, which is located in north-east of Mashhad, Iran. The analysis was based on 14030 records of lambs and 4371 records of ewes. Investigated traits were litter size at birth (LSB), litter size at weaning (LSW), litter mean weight per lamb born (LMWLB) and litter mean weight per lamb weaned (LMWLW) as basic traits, total litter weight at birth (TLWB) and total litter weight at weaning (TLWW) as composite traits. Genetic analysis of the studied traits was performed applying restricted maximum likelihood (REML) procedure by fitting a linear mixed animal model. Direct heritability estimate for LSB, LSW, LMWLB, LMWLW, TLWB and TLWW were 0.10, 0.08, 0.13, 0.07, 0.12 and 0.05, respectively. Corresponding values for repeatability estimates were 0.18, 0.17, 0.19, 0.15, 0.18 and 0.15, respectively. Direct genetic correlation estimates among the studied traits varied from -0.52 for LSW and LMWLB to 0.99 for TLWB and TLWW. Phenotypic and environmental correlation estimates were generally lower than those of genetic ones. Although low direct heritability’s were estimated for the reproductive traits, as these traits are of interest then they used as the primary selection criterion to bring about genetic improvement in ewe productivity traits. تفاصيل المقالة

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6 - Estimation of Genetic Parameters and Genetic Trends of Somatic Cell Score in Iranian Holstein Cows Using Test-Day Records
K. Kheirabadi S. Alijani

The aim of the present study was to estimate the genetic parameters and genetic trends of somatic cell score (SCS) in the first 3 lactations of Iranian Holstein cows by random regression (RR) animal model by using Restricted Maximum Likelihood (REML) method. The data se أکثر

The aim of the present study was to estimate the genetic parameters and genetic trends of somatic cell score (SCS) in the first 3 lactations of Iranian Holstein cows by random regression (RR) animal model by using Restricted Maximum Likelihood (REML) method. The data set used in this analysis included observations of 340318 test-day records of 41526 cows in 288 herds; 89969 test-day of 11750 cows in 127 herds and 20010 test-day of 2461 cows in 60 herds in the first-, second- and third-parity, respectively, during the period from 2002 to 2010. Fixed effects considered were: year of calving, age-season of calving (by applying a fixed regression for each subclass of this effect) and herd-test date. Estimates of additive genetic variances for all parities, with only small changes, show a similar trend. Heritability estimates for first parity (0.03 to 0.07) were lower than those for second (0.07 to 0.11) and third (0.08 to 0.17) parities. Genetic correlations between daily SCS within parity were high for adjacent tests and low between the beginning and the end of lactation and decreased with increase parity number. Genetic correlations between parities were higher than 0.70 but environmental correlations between parities were in range of 0.22 to 0.51. Genetic correlations between parity demonstrate that genes that control SCS in parities are same and selection animal for SCS in first parity would have affected SCS in other parity. The genetic trend for SCS was favorable until 1995 and unfavorable since then. The relatively high level of SCS and positive genetic trends (0.431 to 0.701 cells/mL/year) would suggest that genetic improvement of SCS is at unacceptable level in Iran. تفاصيل المقالة

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7 - Estimates of Repeatability and Heritability of Productive Trait in Holstein Dairy Cattle
ز. عرفانی اصل ع. هاشمی م. فرهادیان

Dairy cattle breeding programs have been based in the selection for traits related to milk production. In this research a data set of 63 herds of East Azerbaijan province Holstein cattle, collected during 2002-2013 by the Iranian Animal Breeding Center was used to estim أکثر

Dairy cattle breeding programs have been based in the selection for traits related to milk production. In this research a data set of 63 herds of East Azerbaijan province Holstein cattle, collected during 2002-2013 by the Iranian Animal Breeding Center was used to estimate the repeatability and heritability of three traits of economic importance. Genetic parameters for first three lactations of Holstein cows were estimated using repeatability models. Single-trait repeatability models were fitted for milk, fat and protein yields. The model contained milk frequency and herd-year-months of test-days (HTD) as fixed effects; effect of animals were the random effects. The estimated heritabilities in first three lactations for milk yield were 0.154, 0.263 and 0.334, for protein yield 0.134, 0.166 and 0.274 and for fat yield 0.059, 0.083 and 0.052. The estimated repeatability in first three lactations for milk yield were 0.475, 0.847 and 0.898, for protein yield 0.398, 0.479 and 0.678 and for fat yield 0.198, 0.281and 0.279. The results imply that milk traits for Holstein dairy cattle in east Azerbaijan, Iran are more heritable. Therefore, these traits can be employed by breeders as selection criteria in developing effective genetic improvement programs. تفاصيل المقالة

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8 - Estimation of Genetic and Phenotypic Parametersof Some Reproductive Traits of Black Bengal Does
ام.ام. میا ام.آ.ام.ی. خاندوکر اس.اس. هوساین ام.او. فاروق دی.آر. نوتر

The objective of this study was to evaluate genetic and phenotypic parameters for some reproductive traits of Black Bengal does. Genetic parameters were estimated by Residual Maximum Likelihood procedure, fitting an animal model ignoring maternal genetic or permanent en أکثر

The objective of this study was to evaluate genetic and phenotypic parameters for some reproductive traits of Black Bengal does. Genetic parameters were estimated by Residual Maximum Likelihood procedure, fitting an animal model ignoring maternal genetic or permanent environmental effects. The least-squares means of litter size at birth (LSB), litter size at weaning (LSW), litter weight at birth (LWB), litter weight at weaning (LWW) and gestation length were 1.50, 1.29, 1.58 kg, 6.37 kg and 144.71 days, respectively. The effect of parity of doe was significant for LSB, LSW, LWB and LWW. In general, LSB, LSW, LWB and LWW increased with the progress of parity. The effect of season of kidding was significant for LSW, LWB and LWW. Estimates of heritability for LSB, LSW, LWB, LWW and gestation length were 0.08, 0.13, 0.10, 0.00 and 0.18, respectively. The low estimates of heritability obtained for reproductive traits indicated that selection based on the doe’s own performance may result in slow genetic improvement. تفاصيل المقالة

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9 - Estimation of Genetic Parameters for Milk Production Trait in Holstein Cows of the Mazandaran Gavdasht Herd Using Test Day Records
ش. قره‪ ویسی ر. عبدالله‪پور

Random regression models (RRM) are used for genetic estimations of milk traits in dairy cows. RRM utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. In this study, to estim أکثر

Random regression models (RRM) are used for genetic estimations of milk traits in dairy cows. RRM utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. In this study, to estimate genetic parameters for milk production trait, test day records (TDR) were collected from the first lactation of Holstein cows from a Mazandaran Gavdasht herd during the years 2001 to 2012. The data included 14150 TDR of milk production trait of 1460 Holstein cows. Analysis of TDR was performed using the DFREML software. The random regression was fitted according to the Legendrepolynomials model from days of lactation. The minimum of heritability (0.04) was estimated for the early lactation period and increased in the late of lactation, about the month 9 of lactation to its peak (0.29). The phenotypic variance was not same during the lactation period and it was too much in the early and late of lactation. The maximum of genetic variance was at the month 10 (19.81) and the minimum at the early of the lactation period (2.51). The residual variances were constant. The maximum of the genetic and phenotypic correlations were observed between adjacent days for milk production trait. Using TDR, accuracy of genetic parameter estimation was increased. تفاصيل المقالة

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10 - Genetic Evaluation of Growth Traits of Black Bengal Goat
ام.ام. میا ام.آ.ام.ی. خاندوکر اس.اس. هوساین ام.او. فاروق دی.آر. نوتر M.N. Haque

Black Bengal goat is the heritage and one of the potential genetic resources of Bangladesh. Least-squares means for body weights at birth, 3, 6, 9 and 12 months of age were 1.09, 5.12, 8.02, 10.92 and 14.47 kg, respectively. Sex of the kid has significant (P<0.05) ef أکثر

Black Bengal goat is the heritage and one of the potential genetic resources of Bangladesh. Least-squares means for body weights at birth, 3, 6, 9 and 12 months of age were 1.09, 5.12, 8.02, 10.92 and 14.47 kg, respectively. Sex of the kid has significant (P<0.05) effect on body weights at 6, 9 and 12 months of age. Type of birth and parity of the dam has significant (P<0.01) effect on birth weight only, whereas season of birth affected (P<0.05) all the body weight traits. Heritability estimates for body weights at birth, 3, 6, 9 and 12 months of age were 0.45, 0.47, 0.45, 0.49 and 0.47, respectively. Genetic correlations between body weight traits ranged from 0.34 to 0.83, whereas phenotypic correlations ranged from 0.34 to 0.90. The high heritability estimates obtained for body weights indicated that mass selection would generate substantial selection responses at all stages of growth. تفاصيل المقالة

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11 - برآورد پارامترهای ژنتیکی صفت تولید شیر گاوهای نژاد هلشتاین مهدشت ساری با استفاده از رکوردهای روز آزمون
شهاب الدین قره ویسی روح الله عبدالله پور ذبیح اله کالاشی

به منظور برآورد پارامترهای ژنتیکی صفت تولید شیر، از رکوردهای روز آزمون مربوط به اولین دورۀ شیردهی گاوهای هلشتاین مهدشت ساری که طی سال های1380 الی 1388 جمع آوری شده بود، استفاده گردید. داده های مورد بررسی در این تحقیق شامل 9782 رکورد روز آزمون مربوط به 1140 رأس گاو هلشتا أکثر

به منظور برآورد پارامترهای ژنتیکی صفت تولید شیر، از رکوردهای روز آزمون مربوط به اولین دورۀ شیردهی گاوهای هلشتاین مهدشت ساری که طی سال های1380 الی 1388 جمع آوری شده بود، استفاده گردید. داده های مورد بررسی در این تحقیق شامل 9782 رکورد روز آزمون مربوط به 1140 رأس گاو هلشتاین موجود در مجتمع شیر و گوشت مهدشت ساری بود. آنالیز رکوردهای روز آزمون با استفاده از نرم افزار DFREMLانجام شد. تابعیت ثابت و تصادفی طبق چند جمله ای های لژاندار از روزهای شیردهی در مدل منظور گردید. همچنین از مدلی با درجه برازش 3 برای عوامل ژنتیکی افزایشی و محیطی دائمی استفاده گردید. حداقل میزان وارثت پذیری مربوط به اوایل دورۀ شیردهی بود(039/0 ) و مقدار آن در اواخر دوره شیردهی افزایش و در حدود ماه نهم از دوره شیردهی به حداکثر مقدار رسید(280/0). مقدار واریانس فنوتیپی صفت تولید شیر در طول دورۀ شیردهی یکسان نبوده و مقدار آن در اوایل و اواخر دورۀ شیردهی بیشتر بود. حداکثر میزان واریانس ژنتیکی افزایشی در ماه دهم(750/18) و حداقل میزان آن در اوایل دوره ی شیردهی(360/2) برآورد گردید. واریانس باقیمانده صفت تولید شیر ثابت بود. حداکثر میزان همبستگی های ژنتیکی افزایشی و فنوتیپی بین روزهای شیردهی مجاور مشاهده گردید و مقدار این همبستگی ها به موازات افزایش فاصله بین روزهای شیردهی کاهش یافت. با استفاده از رکوردهای روز آزمون، دقت برآورد پارامترهای ژنتیکی افزایش یافت. تفاصيل المقالة

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12 - ارزیابی ژنتیکی صفات فیزیولوژیکی مرتبط با تحمل به خشکی در برخی از ژنوتیپ‌های گندم نان در شرایط دیم
زهرا مروتی عزت اله فرشادفر محمد حسین رومنا

چکیده:به منظور بررسی ارتباط فنوتیپی و ژنوتیپی میان خصوصیات فیزیولوژیک مرتبط با تحمل به خشکی و همچنین بررسی تنوع ژنتیکی و برآورد پارامترهای ژنتیکی این شاخصه‌ها در شرایط کشت دیم، 19 ژنوتیپ گندم نان در قالب طرح بلوک‌های کامل تصادفی با سه تکرار در مزرعه تحقیقاتی پردیس کشاور أکثر

چکیده:به منظور بررسی ارتباط فنوتیپی و ژنوتیپی میان خصوصیات فیزیولوژیک مرتبط با تحمل به خشکی و همچنین بررسی تنوع ژنتیکی و برآورد پارامترهای ژنتیکی این شاخصه‌ها در شرایط کشت دیم، 19 ژنوتیپ گندم نان در قالب طرح بلوک‌های کامل تصادفی با سه تکرار در مزرعه تحقیقاتی پردیس کشاورزی و منابع طبیعی دانشگاه رازی کرمانشاه در طول سال 94-1393 کشت گردید. تجزیه واریانس نشان داد که اختلاف معنیداری بین ژنوتیپ‌های مورد ارزیابی از نظر صفات عملکرد دانه، پایداری غشا، میزان آب نسبی ازدسترفته، آب ازدسترفته برگ، آب حفظشده برگ، کارایی مصرف آب و میزان سبزینگی برگ در شرایط کشت دیم وجود دارد. نمای چندضلعی بایپلات ژنوتیپ - صفت نشان داد که ژنوتیپ شماره 12 (wc-4931) برترین ژنوتیپ نسبت به سایر ژنوتیپ‌های مورد بررسی از نظر عملکرد دانه، راندمان مصرف آب، آب نگهداری شده در برگ‌های بریده‌شده و میزان سبزینگی برگ بود. رابطه ژنتیکی مثبت و معنی‌داری میان راندمان مصرف آب و عملکرد دانه، میان کارایی فتوشیمیایی فتوسیستم II و آب ازدست‌رفته برگ و میان آب نگهداری شده در برگ‌های بریده‌شده و درجه سبزینگی برگ مشاهده شد. از طرف دیگر، وراثت‌پذیری و پیشرفت ژنتیکی بالا برای عملکرد دانه، پایداری غشا و راندمان مصرف آب مشاهده شد که حاکی از عمل افزایشی ژن‌ها است. براین‌اساس، با توجه به سهم بالای اثرات افزایشی در صفات پایداری غشا، عملکرد دانه و راندمان مصرف آب، انتخاب در نسل های اولیه در برنامه اصلاحی پیشنهاد میشود. تفاصيل المقالة

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