Browsing by Author "Sartie, Alieu Mortuwah"
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- ItemEffectiveness of botanical preparations for the control of rice weevil (Sitophilus oryzae) during rice seed storage and their impact on the rice seed viability : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Seed Technology at Massey University, Palmerston North, New Zealand(Massey University, 2001) Sartie, Alieu MortuwahFood security and the maintenance of seed quality from harvest to planting are key issues for peasant farmers. In Sierra Leone, up to 28% of rice seed can be damaged by rice weevil in the six months storage period. The use of chemical insecticides to control this insect is not practical for traditional farmers. Some tribes use pepper powder (Capsicum spp.) as a seed protectant. In this study, I have compared the effects of neem (Azadirachta indica) oil, neem powder, pepper (Capsicum frutescens cv. "Habanero") powder and lentil (Lens culinaris cv. "Raja") powder on the survival of adult rice weevil (Sitophilus oryzae) and weevil offspring during rice (Oryza spp.) seed storage, and on the germination of the rice. Treatment of stored rice with neem oil, neem powder and lentil powder gave some protection from rice weevil damage. Neem oil at the rate of 0.005ml/kg rice seed effectively controlled weevil damage without reducing the seed germination. Lentil and neem powders at the rate of 0.02g/kg rice seed gave effective protection against rice weevil damage with no reduction in viability of the seeds. Pepper powder did not kill adult rice weevil. Neem oil reduced the development of weevil offspring in rice seed, but the powders of neem, lentil and pepper did not. Low relative humidity of 42.5% in seed storage environment and a reduction in seed moisture content below 10% enhanced the mortality of adult rice weevils on rice seed.
- ItemPhenotypic assessment and quantitative trait locus (QTL) analysis of herbage and seed production traits in perennial ryegrass (Lolium perenne L.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (Ph. D.) in Plant Science, Institute of Natural Resources, College of Sciences, Massey University, Palmerston North, New Zealand(Massey University, 2006) Sartie, Alieu MortuwahThe aims of this study were to develop a genetic linkage map of perennial ryegrass, identify quantitative trait loci (QTL) for herbage and seed production traits, and to identify DNA markers associated with QTL for use in marker-assisted selection (MAS). Major traits identified for herbage production were leaf elongation rate (LER), leaf lamina length (LL), tiller number (TN) and tiller weight (TW), and for increased seed production were seed yield per head (SdYH), reproductive tiller number (RT), reproductive tillers with matured heads (TMH), florets per head (FH), spikelets per head (SH), florets per spikelet (FS), floret site utilization (FSU) and seed weight (TSW). A genetic linkage map spanning 582 centimorgans (cM) was constructed with EST-SSR (simple sequence repeat markers derived from expressed sequence tags) and used to identify QTL for herbage dry weight (DW) and seed yield per plant (SdYP), and their key component traits. Significant genotype by environment effects were encountered for herbage yield, with fewer QTL identified in spring than in autumn. For some traits, ranking of genotypes differed greatly between seasons and different QTL were identified. QTL for DW were identified on linkage groups (Lg) 1 and 6. The QTL on Lg 6 co-located with QTL for TN, while that on Lg 1 co-located with LER and LL. Markers at Lg 1 QTL (qDW-03-1.1) may be more useful for increasing herbage production by MAS because selection for high LER and long LL has been suggested to increase herbage production in perennial ryegrass. QTL for SdYP were identified on Lg 2 and Lg 6. The QTL on Lg 6 co-located with QTL for SdYH, FSU and TSW, while that on Lg 2 co-located with FH, SH and FS. For seed production, markers at Lg 6 QTL (qSdYP-03-6) may be very useful because this QTL co-located with QTL for SdYH, FSU and TSW, and SdYH has been identified previously as a key selection criterion for increasing seed yield. Marker-trait validation confirmed markers pps0495 and pps0698 identified by QTL analysis to be potentially useful for selecting for fast leaf appearance and long LL, respectively, in perennial ryegrass.