عنوان
پدید آورنده
موضوع
رده
کتابخانه
محل استقرار
شماره کتابشناسی ملی
شماره
TLpq304463690
زبان اثر
زبان متن نوشتاري يا گفتاري و مانند آن
انگلیسی
عنوان و نام پديدآور
عنوان اصلي
Studies on the biology of Striga aspera (Scrophulariaceae) in Nigeria
نام عام مواد
[Thesis]
نام نخستين پديدآور
E. I. Aigbokhan
نام ساير پديدآوران
L. J. B. Musselman, Dana K.
وضعیت نشر و پخش و غیره
نام ناشر، پخش کننده و غيره
Old Dominion University
تاریخ نشرو بخش و غیره
1998
مشخصات ظاهری
نام خاص و کميت اثر
135
یادداشتهای مربوط به پایان نامه ها
جزئيات پايان نامه و نوع درجه آن
Ph.D.
کسي که مدرک را اعطا کرده
Old Dominion University
امتياز متن
1998
یادداشتهای مربوط به خلاصه یا چکیده
متن يادداشت
Studies on Striga aspera are few and little information exists on its relationship with the morphologically similar and much studied S. hermonthica. Both species are sympatric in West Africa and if they hybridize, may serve as virulent gene reservoirs for each other. The primary focus of this study was on the biology of S. aspera in Nigeria. The research focussed on its distribution, phenology, cytology, hybridization, seed dormancy, viability and germination in relation to S. hermonthica. Related studies involving the hybrids include genetic and morphological variability, pathogenicity and the simultaneous dual infection of a maize plant by both species. In Nigeria, Striga aspera was less widespread than S. hermonthica and native grasses growing along road borders were their common host. A new procedure developed for counting mitotic chromosomes in Striga established new chromosome counts of n = 18 for Striga aspera and n = 19 for Striga hermonthica. Hybridization success between both species ranged from 68 to 95%. Seed derived from all crosses were viable, germinable and was pathogenic on maize. Reduced viability and germination of seeds from the hybrids suggest that the two species were not 100% compatible. Similarity between Striga aspera and S. hermonthica was 55% genetically and 50% morphologically. The F hybrids were morphologically intermediate to the parents, but showed closer genetic affinity to their respective maternal parents. Morphological analysis of wild and hand-pollinated populations grouped some F hybrids with samples from the wild population suggesting that hybrids may exist in nature. The pathogenicity of Striga aspera (SA), S. hermonthica (SH) and their F hybrids on maize in order of decreasing aggressiveness was as follows: SH/SA > S. aspera > S. hermonthica > SA/SH. This differential aggressiveness on maize suggests that hybrids may be a source of virulent strains in Striga populations. Both species can parasitize a maize plant simultaneously. Striga aspera and S. hermonthica were biologically closer than earlier envisaged. Their ability to cross successfully suggests that their separation at the species level may be too complete. A separation at the subspecies level seems more plausible. The aggressiveness of S. aspera on maize implies that it is a potential threat to future maize production in Africa.
موضوع (اسم عام یاعبارت اسمی عام)
موضوع مستند نشده
Biological sciences
موضوع مستند نشده
Botany
موضوع مستند نشده
Ecology
موضوع مستند نشده
Plant pathology
موضوع مستند نشده
Plant pathology
موضوع مستند نشده
Striga hermonthica
نام شخص به منزله سر شناسه - (مسئولیت معنوی درجه اول )
مستند نام اشخاص تاييد نشده
E. I. Aigbokhan
مستند نام اشخاص تاييد نشده
L. J. B. Musselman, Dana K.
دسترسی و محل الکترونیکی
نام الکترونيکي
مطالعه متن کتاب وضعیت انتشار
فرمت انتشار
p
اطلاعات رکورد کتابشناسی
نوع ماده
[Thesis]
کد کاربرگه
276903
اطلاعات دسترسی رکورد
سطح دسترسي
a
تكميل شده
Y
