Browsing by Author "Audrie, K.H."
Now showing 1 - 3 of 3
- Results Per Page
- Sort Options
Item East African Work on Breeding Maize Resistant to the Tropical American Rust, Puccinia Polysora(1957) Baldwin, B.J.T.; Audrie, K.H.; Storey, H.H.; Dixon, G.E.; Hemingway, J.S.; Jameson, J.D.; Thorpe, H.C.; East African Agricultural and Forestry Research Organization: Tanganyika Agricultural Corporation: Uganda Department of Agriculture: Kenya department of AgricultureSince 1952 Puccinia polysora under has become widespread in maize in the tropical areas of East Africa, and severe attacks have been shown to reduce yield greatly. Two physiologic races have been recognized, 'EA.I' being today the prevalent race in the field and 'EA.2' being known as yet only in the Muguga glasshouses. Experimental infection trials in glasshouses at Muguga, Kenya, failed to demonstrate resistance in any African maize variety; but among maize’s imported from Central America and the Caribbean plants were found that showed the hypersensitive type of resistance. From these, lines were bred that were pure for either of two genes: Rppl. conferred high resistance to Race EA.I but none to EA.2; while Rpp2 conferred a lesser, but effective, resistance equally to both rust races. Field breeding at three stations in East Africa was successful in incorporating each of these genes separately in locally adapted maize varieties; and considerable bulks of pure-breeding resistant maize’s were expected to become available during 1957 and later years.Item Inheritance of resistance in maize to the virus of streak disease in East africa(1967) Storey, H.H.; Audrie, K.H.; East African Agriculture and Forestry Research OrganizationMaize plants selected from lines raised in South Africa, and resistant to an East African isolate of streak virus, gave rise on selfing to lines that bred true for resistance through four generations. Heterozygotes from crossing resistant by susceptible lines reacted to infection by inoculation with the vector in a manner intermediate between the parents; neither allelomorph was fully dominant. The F2 generation from the cross segregated in the expected 1: 2: 1 ratio. Backcrosses segregated 1: 1. The evidence is interpreted as showing …Item Transfer of resistance to the Streak Virus into East African Maize(1967) Audrie, K.H. ; Storey, H.H.; E.A.A.F.R.O., Kikuyu, KenyaStreak disease is caused by infection with a virus that is prevalent in maize and some grasses in many parts of Africa. It has been frequently described (eg Storey, 1925; McClean, 1947); typically it results in leaves developing with a nearly uniform pattern of chlorotic and green areas; in its most severe form some half or more of the total leaf area may be chlorotic, and in this form the disease causes a marked reduction in the growth and productivity of the plant. Because the virus is transmissible only by a specific insect vector of the genus Cicadulina (Storey, loc. cit.) and by no other known means, prevalence of the disease in the field is dependent not only on the presence of the virus but also on the frequency with which the vector occurs. In consequence, outbreaks of streak disease may vary from season to season and from place to place. Nevertheless, in aggregate the disease can cause large losses in productivity of maize; and a search for resistant maize types is justified. Glasshouse studies of streak resistance in maize have been prosecuted over a number of years at EAAFRO That this resistance existed had been recognized in the early thirties in South Africa, but owing to difficulties inherent in studies of this problem under field conditions, research workers there had been unable to arrive at any hypothesis for the manner in which resistance was inherited (Rose 1938; Gorter, 1959). The purpose of the work at EAAFRO was to see whether a genetic hypothesis would emerge from studies carried out under the more exact, more reliable and more rapid conditions provided by
