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    Seed quality and storage performance in mungbean and peanut : a thesis presented in partial fulfilment of the requirement for the degree of Master of Agricultural Science in Seed Technology, at Massey University, Palmerston North, New Zealand
    (Massey University, 1996) Supradith, Uraiwan
    Five seedlots of mungbean and three seedlots of peanut were assessed for seed quality using six standard laboratory tests ie. purity analysis, seed moisture content, germination, seed health, and two vigour tests (accelerated ageing, and conductivity (electrolyte leakage)). These testing methods were valuable as the results allowed distinction of quality differences between seedlots which were used to explain the possible cause or causes of poor quality in each seedlot, eg. high seed moisture content, low viability or vigour, mechanical damage, or fungal infection. The three highest quality seedlots of mungbean (lot 1 cv. Chinese, lot 2 cv. Berken, and lot 3 cv. Regur) and one seedlot of peanut (cv. Spanish White) were identified (germinations 88, 94, 94 and 72 percent before, and 55, 51,66 and 67 percent after accelerated ageing), and selected to use in a subsequent seed storage experiment. Seeds were stored under different conditions involving two seed moisture contents (8.6% and 13.4% for mungbean, and 6.6% and 11.5% for peanut), two storage containers (in aluminium foil packets representing sealed storage, and muslin cloth bags representing open storage) and various temperature/ relative humidity regimes (30°C/95%RH and 20°C/75%RH for mungbean, and 30°C/50%RH. 20°C/75%RH. 5°C/85%RH . and 30°C/95%RH (open storage only) for peanut). Effect of initial seed moisture content or relative humidity, packaging and temperature on seed moisture content, germination percentage, conductivity leachate and seed health of each lot was studied at two monthly intervals during an up to eight months storage period. In all cases, deteriorative changes were higher in open storage at high relative humidity (95%) at 30°C than at lower level relative humidity and temperature regimes. At 30°C/95%RH. seed moisture content of both mungbean and peanut seed open stored initially at low and high moisture content increased markedly to equilibrium with the prevailing relative humidity (15-18.4%SMC in mungbean and 12.4-12.7%SMC in peanut at 2 months storage). Under these conditions all seed all seedlots lost germination after one month (peanut) or six months (mungbean) and loss of electrolytes from seeds into steep water also increased markedly with increasing storage time. Levels of infection by field fungi decreased rapidly with a concomitant rapid increase in invasion of storage fungi, such as Aspergillus glaucus, A. flavus, A. candidus, A. ochraceus A. niger and Penicillium spp. Open stored dry and wet seedlots at lower temperatures/relative humidities of 20°C/75%RH for mungbean, and 30°C/50%RH. 20°C/75%RH, or 5°C/85%RH for peanut, reached equilibrium moisture contents oft 11.3-12.7%, 3.8, 6.5, and 7.2% after 8 months storage, respectively. Mungbean seed germination and vigour was maintained appreciably for 8 months, while peanut seed stored at an initially high moisture content showed a marked decrease in quality, particularly at 30°C. Fungal infection was generally low. Throughout the storage period seed moisture content in sealed storage at all temperatures did not change from initial levels (8.6% or 13.4% in mungbean and 6.6% or 11.5% in peanut). Initial seed moisture content greatly affected seed germination, conductivity leachate and fungal infection, particularly in peanut seeds. Loss of peanut seed germination and seed vigour both increased with increasing seed moisture content and storage temperature. Peanut seeds stored at a higher initial level (11.5%SMC) lost all germination after 2 months storage at 30°C, after 6 months at 20°C and retained near initial levels of germination after 8 months at 5°C. In mungbean seeds stored at 13.5% SMC, seed germination and vigour were affected after 8 months storage at 30°C, particularly in poorer quality lots. The main storage fungal infection was A glaucus but at low levels in all cases. Deteriorative changes were more rapid in initially poorer quality lots than in initially higher quality lots of both mungbean and peanut seed.
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    Seed quality and storage performance of wheat (Triticum aestivum.) and Soybean (Glycine max (L) Merrill) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agriculture Science in Plant Science (Seed Technology) at Massey University, Palmerston North, New Zealand
    (Massey University, 1996) Singkanipa, Varenya
    Five seedlots of wheat (Triticum spp.)cvs. Norseman. Otane, Karamu and two unknown cultivars. and four seedlots of soybean (Glycine max (L) Merrill)cv. Davis, two seedlots of cv. CH187 and one unknown cultivar were assessed for prestorage quality by using different laboratory methods ie purity, thousand seed weight, seed moisture content, germination, accelerated ageing, conductivity and seed health. The results of this study showed quality differences between seedlots of both wheat and soybean. Using seed germination and vigour data, three lots of wheat with high quality, two seedlots of soybean with high quality and one seedlot with low quality were chosen and adjusted to two different seed moisture contents (10% and 14% in wheat .and 8% and 12% in soybean). Seed samples of both species were stored in open storage (muslin bags) or sealed storage (aluminium foil packets) at 20°c 75%RH or 30°c 50% RH for 8 months. All wheat seedlots and two soybean seedlots were also stored under open storage at 30°c 95%RH. Seed quality was assessed at intervals of 1,2,4, 6 and 8 months. The seed moisture content of both species in open storagechanged to reach equilibrium moisture content (EMC) with the prevailing relative humidity. At 30°c 95%RH moisture content of wheat and soybean seeds increased up to 18.5-20.5% and 22-23%. respectively while at the same temperature but lower RH (50%), SMC fell to 8.2-8.5% and 5.2-5.5%, respectively. Both low and high initial SMC of seed stored at 20°c 75%RH either increased or decreased to reach an EMC of 12.8-13.6% for wheat and 9.8-10.1% for soybean. Under sealed storage at different storage temperatures and relative humidities SMC did not change from initial levels. At 20°c 75%SMC the type of storage container had no significant effect on germination percentage or conductivity in wheat and soybean after 8 months. At 30°c, however, the germination percentage of wheat and soybean with high initial SMC in sealed storage and in open storage high RH declined more rapidly during storage than the other treatments. Germination percentage correlated reasonably well with conductivity, with conductivity readings increasing as vigour decreased. At 30°c 95% both open and sealed storage at high initial SMC resulted in seed showing a conductivity value increase with longer storage time, indicating seedlot deterioration. All field fungi were eliminated from seed open stored at 30°c 95% but storage fungi developed rapidly in all seedlots after two months. The main genus involved was Aspergillus spp. but Penicillium spp. were also found at low levels in soybean. However, under 30°c 50%RH and 20°c 75%RH storage conduction field ftingi levels in wheat and soybean were reduced during storage and seed was either disinfected or remained infected at only low levels after 8 months storage. The main field fungus present in wheat was Fusarium spp.. In soybean both Fusarium spp. and Alternaria spp. survived well along with low levels of Colletotrichum spp.. The implications of pre-storage seed quality, seed moisture levels and storage environment and their effects on seed deterioration rate and extent are discussed. The role of field and storage fungi in affecting loss of seed viability in storage and the possibility of exploiting the storage environment to obtain pathogen free seed for planting is also considered.
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    Seed dormancy and germination of a panel of New Zealand plant species : Carex trifida, Corposma robusta, Cyperus ustulatus, Hebe stricta, Muehlenbeckia australis, Myrsine australis, Phormium tenax and Sophora prostrata : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science at Massey University
    (Massey University, 2004) Mackay, Allison
    Literature was reviewed on the germination and possible uses for revegetation of the New Zealand indigenous species selected. Seeds of Carex trifida, Coprosma robusta, Cyperus ustulatus, Hebe stricta, Leptospermum scoparium, Muehlenbeckia australis, Myrsine australis, Phormium tenax, Phormium 'Yellow Wave' and Sophora prostrata were assessed for germination rates, percentage germination, dormancy and the effects that temperature has on germination. Seeds of Carex, Cyperus and Myrsine showed no germination in light or dark at 20°C. In contrast, 12 weeks of low temperature stratification resulted in a high percentage of seed germinating for Carex and Cyperus. There was no germination of Myrsine despite high viability in the initial germination experiment and the stratification experiment. Removal of the endocarp and a period of stratification increased germination percentage of Myrsine to 91%. Germination was low for Muehlenbeckia in the light at 20°C, but 4 weeks of low temperature stratification increased germination rate. After 2 years, 80% of Coprosma seeds germinated but germination rate increased after subjecting the seed to 8 weeks or more of stratification. No seeds of Coprosma or Muehlenbeckia germinated in the dark. Rapid germination of Hebe seeds was obtained, with 100% of the seed germinating in the light while only 7% germinated in the dark. Leptospermum had rapid germination, with 100% germinating in the light, while only 3% germinated in the dark. A low percentage of Phormium seed germinated in both the light and dark in the first month and no further germination was observed. In contrast, 8 weeks or more of low temperature stratification resulted in almost complete germination. There was rapid germination of Sophora seeds with 100% of the seed germinating in the light and dark. Carex seed had a limited temperature range at which it germinated (22°C to 26°C), while Cyperus had a wider range (18°C to 32°C) but did not germinate at low temperatures (6°C to 14°C). The optimum germination range for Cyperus was 24°C to 30°C. Hebe did not germinate at high temperatures (30°C to 32°C) but successfully germinated at all other temperatures with the optimum germination range being 6°C to 24°C. Leptospermum did not germinate at 6°C but had maximum germination at most other temperatures. Muehlenbeckia and Phormium germinated at all temperatures tested (6°C to 32°C) with the most seed germinating at 20°C for Muehlenbeckia and between 14°C to 22°C for Phormium. Sophora did not germinate at the low temperatures (6°C to 10°C). The germination rate increased with temperature for Cyperus, Hebe, Leptospermum, Muehlenbeckia, and Phormium. Generally, for Carex and Sophora as temperature increased germination rate slowed. It appeared that light is required for Hebe and Leptospermum to germinate. Sophora required scarification but not light. Coprosma and Muehlenbeckia required light and a period of chilling to increase the rate of germination. A small percentage of the Phormium population is not dormant but a period of chilling increased the germination percentage for that portion of the population that is dormant. Carex and Cyperus required a period of chilling in order to break dormancy. Myrsine required removal of endocarp and a period of chilling to germinate. A list of cleaning descriptions and the equipment that was used for each species studied is reported. Preliminary results of a hydroseeding trail using the species studied were also reported.