Pulses
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Browsing Pulses by Subject "Food"
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Item Bulrush and finger, millets in Tanzania(1973) Judy, W. H.; Division of Research and Training, Dar es Salaam, TanzaniaYield trials of Eleusine coracana and Pennisetum typhoides are in progress. The sorghum varieties Serena and 50 X 36 have outyielded local varieties by 1.5 to 2 times in trials.Item Crossing of Food Beans (Phaseolus Vulgaris L.): Influence of Environment and Pollination Technique(East African Agricultural and Forestry Journal, 1978) van Rheenen H. A.; The National Horticultural Research Station Thika, Kenya (MOA); The Netherlands Ministry of Foreign AffairsWhen van Rheenen and Gichuhi (1978) wanted to start a breeding programme at Thika, Kenya, they observed that their crosses were successful for 18 percent only while the percentage of natural pod set was 55. Obviously an improvement here was much desired. A literature review and their first experiences suggested some possible ways of improvement. Main factors reported to be of influence on pod set and the success of crossing are relative humidity, temperature and pollination technique. On relative humidity, generally a higher percentage is recommended. Masarova (1969) covered his bean flowers with damp gauze after crossing to maintain a humid environment. Khosh-Khui und Niknejad (1971) protected their crossed chickpea flowers with cheese-cloth bags against wind and sunshine. Mazyed (1973) observed that the optimum relative humidity for crossing beans was between 70 and 90 per cent. Fisher and Weaver (1974) noted in the case of lima beans that a high relative humidity enhanced pod set and pod retention by pro- moting pollen germination. As an exception Davis (1945) reported that minimum relative humidity of minor influence on pod set for white pea beans, but his average humidity figures ranged from 27.8 to 32.3 percent. On temperature: Generally a moderate temperature of around 20°C has been found opti mal, although more extreme temperatures of 35°C and 10°C for instance can be tolerated.. Davis (1945) found maximum daily temperatures to influence pod set more than any other factor he had studied including soil moisture, at low temperatures of 17/10°C. Kooistra (1963) found temperatures between 20°C and 25°C to be optimal for crossing beans. According to Inoue and suzuki (1959) pollen growth down the style is maximal for French beans at temperatures between 15°C and 25°C, but the pistil is receptive at temperatures between 15°C and 40°C. In his field experiments Smith and Pryor (1962) found negative correlation between pod set and maximum temperatures the day before, during, and the day after blooming. The maximum temperatures ranged. from 21 to 47°C. Similarly a negative but less significant correlation existed between between maximum temperature and seeds per pod. El Nadi (1969) grew broad beans at controlled temperatures of 18°C, 24°C and 29°C and ex- perienced less flower shedding at lower tem- perature. Mack and Singh (1969) harvested 22 to 67 percent more food beans from a crop grown in the open than raised in plastic cages and they attributed the yield loss to the high temperature of 34°C in the cages, which ex- ceeded that of the field by 8°C. Optimum temperatures for crossing beans were between 15°C and 25°C for Mazyed (1973). Fisher and Weaver (1974) noted that high temperatures of 27 to 35°C promoted flower opening but affected adversely per pod set and pod retention. Stobbe et al. (1965) grew beans under controlled conditions at day/night temperatures of 24.0/ 15.5°C, 29.5/21.0°C and 35.0/26.5°C and re- corded the highest number of flowers and pods at 29.5/21.0°C. Not only the environment but also the pollination technique is of importance. Buishan (1956) describes a number of crossing methods among which were the rubbing and looking methods and the combination of the two. The Max Plank Institute obtained 70 to 80 percent crossing success with the booking method, while Mazyed (1963) was satisfied with the combined rubbing and hooking method. Polli mation without emasculation possible (Koojstra, 1963, 963, and Retig, 1971), but the risk of unwanted self-pollination is greater and the stigma is more exposed. The present study was understaken to in- vestigate the influence of environment and pollination technique on pod and seed set. It took place at Thika during the second half of 1976.
