Black nightshades, Solanum nigrum L. and related species

The black nightshades (Solanum nigrum and related species in sect. Solanum) are worldwide weeds of arable land, gardens, rubbish tips, soils rich in nitrogen, in moderately light and warm situations which occur from sea to montane levels. They are, however, also widely used as leafy herbs and vegetables, as a source of fruit and for various medicinal purposes. Therefore, human consumption of their leaves and fruits as food is widespread, particularly in Africa and SE Asia. Unfortunately, there is widespread confusion over the precise identification of the taxa involved, especially in those areas in which the species are most commonly used as food sources. This monograph attempts to identify the species related to the black nightshade more accurately, by providing an identification key, descriptions of the taxa most widely reported to be of dietary and/or ethnobotanical use in various Asian, African and Indonesian countries, listing some of the many vernacular names used for the species, recording precise uses of the various species and presenting some information on their genetic resources. Two appendices are included listing (1) research contacts and centres of research, and (2) gene banks maintaining collections. (Abstract © CAB ABSTRACTS, CAB International

Cat's whiskers Cleome gynandra L.

Cat's whiskers (Cleome gynandra) grows as a weed in most tropical countries, but is a semi-cultivated, popular tropical leafy vegetable in many parts of sub-Saharan Africa especially in most countries in eastern and southern Africa. This book presents information on its genetic resources in a series of chapters on the following topics: taxonomy, botany, origin and centre of diversity, properties and uses, characterization, evaluation and conservation, breeding, production, ecology, agronomy, and limitations, prospects and research needs. An appendix details researchers and institutions working on indigenous leafy vegetables in sub-Saharan Africa. (Abstract © CAB ABSTRACTS, CAB International

Cardinal Temperatures and Thermal Times for Vernalisation in Carrot cv. "Nantes"

Effect of temperatures on bolting and flowering, measured as days to internode extension (bolting) and to flower bud visibility, respectively, were studied in carrot (Daucus carota) cultivar (cv.) "Nantes" grown in a controlled environment. All carrot plants raised from stecklings subjected to 10 weeks chilling at 3, 6 and 9 C bolted and flowered under subsequently warmer temperatures (18 C). However, only 33% of the stecklings given 1 and 12 C temperature pretreatments for a similar duration flowered. No flowering was observed for plants whose stecklings were pre-treated at 15 C for 10 weeks or those exposed to 1 C for 5 weeks. Plants chilled for 10 weeks required less days to bolting and flowering (P<O.05) than those chilled for 5 weeks. Rates of bolting and flowering increased linearly with temperatures from 1 to 6 C and declined linearly above 6 to 12 C. The linear relationship enabled the optimum temperatures for vernalisation to be derived as 6 C for both bolting and flowering. Base temperatures of -2.9 and -1.7 C and maximum temperatures of 16.97 and 16.27 C for bolting and flowering, respectively, were also predicted. The minimum thermal time for vernalisation in degree Celcius days (Cd) for any bolting and flowering to occur in this cultivar of carrot was 126 Cd and the optimum for 100% bolting and flowering was about 400 Cd.L'effet de temperatures sur l'elongation des entre-noeuds et la floraison, mesure respectivement en nombre de jours d'elongation d'entrenoeuds et d'apparition de boutons floraux, etait etudie sur le cultivar de carotte "Nantes" plantes en milieu controle. Tousles plants de carotte exposes a 10 semaines de refroidissement de 3, 6, et 9 C se sont etioles et ont fleuri a des temperatures subsequentes chaudes (18 C). Cependant, seulement 33 % de plants ayant recus des pretraitements de temperatures de 1 et 12 C pendant une periode similaire. Les plantes qui n'ont pas fleuri sont ceux qui ont renu un pretraitement de 1 C pendant 10 semaine ou ceux qui etaient exposes a la temperature de 1 C pendant 5 semaines. Les plants refroidis pendant 10 semaines exigeaient peu de jours pour l'elongation des entrenoeuds et la floraison (P<0.05) par rapport a ceux refroidis pendant 5 semaines. Les taux d'elongation et de floraison augmentaient lineairement a des temperatures de 1 a 6 C, et decroissaient lineairement au dessus de 6 a 12 C. La relation lineaire a permi d'ajuster l'optimum de temperatures de vernalisation a 6 C pour aussi bien l'elogation d'entrenoeuds que la floraison. De meme, il etait bien possible de predire que pour l'elongation et la floraison, les temperatures extreme etaient -2.9 et 16.97, et -1.7 et 16.27 C respectivement. Le temps thermal minimum en degres celcius parjour de vernalisation pour que l'elongation. et la floraisonaient lieu sur ce cultivar de carotte etait de 126 Cd tandis que l'optimum pour avoir 100% d'elongation et de floraison etait environ 400 Cd

Effect of different temperature regimes on vegetative growth of melon plants

Experiments were conducted at the Institutes for Applied Research in Beer-Sheva, Israel between November 1992 and April 1993 to study the effects of different temperature regimes on vegetative growth of thirteen melon (Cucumis melo L.) cultigens and to identify rapid and reliable selection criteria for breeding for cold resistance. The cultigens were grown in greenhouses at two temperature regimes: high and low with mean minimum and maximum temperatures of 13 and 34 C, and 8 and 33 C, respectively. The cultigens were examined for the rate and amount of vegetative growth which included lengths of mainstems, number of nodes, internode lengths and leaf chlorophyll content. Variation among the cultigens both between and within temperature regimes was significant for most of the traits. The best six cultigens for tolerance to suboptimal growing temperatures were Cinco, Midget, BsFDHK, Tal Dvash, H17 and H19. These cultigens were found to perform better, but not necessarily to the same degree in the low temperature regime for all the traits considered than the other cultigens examined. Relative growth rate (RGR) was found to be superior over the rest of the traits in distinguishing between cold sensitive and cold tolerant lines. It could, therefore, serve as a rapid and reliable selection criterion for breeding for cold tolerance in melons.Des experiences sur la croissance de "cultivars" de treize melons (Cucumis melo L.) ont ete menees a l'institut de recherces appliquees de Beer Sheva (Israel) entre novembre 1992 et Avril 1993. Ces experiences ont etudie l'incidence de differents regimes de temperature sur la croissance des cultivars, et cherche a identifier des criteres de selection rapides et fiables pour l'aquisition de la resistance au froid. Les cultigens ont pousse dans des serres a des regimes de temperatures differents; respectivement 1) 13 a 34 C et 2) 8 a 33 C. Ces cultivars ont ete examines en fonction de taux de croisssance vegetative (longueur de la branche centrale, nombre de noeuds, espace entre les noeuds et teneur en chlorophylle). La variation parmi les cultivars entre differents regimes et dans les memes regimes de temperature s'est averee significative pour la plupart des plants. Les six meilleurs cultivars resistants a une temperature suboptimale sont Cinco Midget, BsFDHK, Tal Dvash, H17 et H19. Ces cultivars se sont montres plus performants mais pas necessairement a la meme temperature dans les bas regimes, que les autres plants si l'on distingue la sensation au froid et les lignes de tolerance au froid. Des lors, cela pourrait constituer des criteres de selection rapides et fiables pour acquerir la tolerance au froid

The biodiversity of traditional leafy vegetables

There is an undervalued reservoir of diversity of African Leafy Vegetables. These vegetables are extremely important for food security, nutrition and poverty alleviation throughout Africa. However, the reservoir is under threat because the vegetables are being displaced in many areas. There is a decline in the production, utilization and diversity of these vegetables. The decline will have a significant impact on the nutritional status of households and incomes of women farmers who are the primary producers, transformers and sellers of these plants. In response to this threat to Africa's crop genetic diversity and its food security, IPGRI convened several workshop where national plant genetic resources programmes could identify priority species and carry out actions to stem this threat. The results of those actions are contained in this book, which is the latest step forward in the commitment IPGRI has to the conservation and sustainable utilization of genetic resources in Africa. The book contains authored chapters by national scientists on the diversity and uses of leafy traditional vegetables in Botswana, Cameroon, Kenya, Senegal and Zimbabwe. The conclusions outline ways that the great potential of Africa's plant genetic resources that can be used to improve the welfare of African communities

The effect of different agroecological zones and plant age on the cyanogenic potential of six cassava clones

The effects of plant age on the cyanogenic potential (CNP) of leaves (CNP-L) and storage roots (CNP-R) of selected cassava clones, TMS 30001, TMS 4(2)1425, TME1, TME2,Isunikankiyanand Dakata Wariya were studied in two agroecological zones in West Africa. The two zones were represented by Kano in the Sudan Savanna zone with a unimodal annual rainfall averaging 844 mm and Ibadan in the forest-savanna transition zone with a bimodal rainfall averaging 1253mm per year. Plants were sampled periodically throughout the growing period. Highly significant correlation coefficients were obtained between CNP-L and CNP-R implying that CNP-R could be predicted from CNP-L, thus destructive sampling may not be necessary for determining CNP-R. Both CNP-L and CNP-R were much higher in Kano than in Ibadan at all sampling times. These results indicate that CNP was greater in the drier ecozone and suggests that both plant age and location were influencing the CNP of cassava roots and leaves. At both Kano and Ibadan, cassava CNP-R was lowest in cultivar TME1 and highest in TMS 50395. I leaves, CNP-L was highest in TMS 50395 and lowest in Isunikankiyan