In an attempt to set up habitat management strategy against Eldana saccharina Walker, an economically important graminaceous stem and cob borer, two laboratory experiments were carried out. The first experiment was designed to assess oviposition preference of E. saccharina for growth stages, plant parts and freshness of different host plants and between host plants species. Zea mays L., Sorghum arundinaceum (Desv.) Stapf, Andropogon gayanus Kunth, Panicum maximum Jacq., Pennisetum polystachion (Linn.) and Cyperus papyrus L. were assessed. Results showed that E. saccharina preferred wild grasses to maize for oviposition. More than 94% eggs were laid on wild grasses. Of all tested grasses, P. polystachion was the most attractive with more than 30% of collected eggs. For all plant species, posttasseling stage was more attractive than the tasseling and pre-tasseling ones. More than 90% of total eggs were laid on dry leaves and sheaths and less than 10% on fresh leaves. Different characteristics relating to population dynamics of E. saccharina were assessed in the second experiment. Larval survival rate was 10% on Z. mays, 0.50% on S. arundinaceum and around 0% on the other wild grasses. Larval development length was longer on S. arundinaceum than on Z. mays. Females reared on Z. mays were three times more fecund than those reared on S. arundinaceum. Complete life table of females from larvae reared on Z. mays was studied.

In most cotton-growing regions of West and Central Africa where rainfed conditions prevail, cropping conditions are highly diversified since the crop is planted over an extended period. We studied production and development patterns in 10 cotton (Gossypium hirsutum) varieties to determine the most efficient strategies that could be transformed into breeding traits. Four trials were carried out between 2002 and 2003 in two cotton-growing areas in Benin to compare the 10 varieties at three stand densities and two planting dates. The parameters monitored were the mean first flower opening date (FF), effective flowering time (EFT), plant height at harvest (HH), height to node ratio (HNR), length of fruiting branch (LFB), number of vegetative branches (NVB) and average boll retention at the first position of the fruiting branches (RP1). We identified two ideotypes that yielded better than the others: (i) Mar 88-214 performed well under late planting-high stand density conditions and was characterized by low vegetative growth and early flowering onset, a short flowering period and low RP1; (ii) H 279-1 performed especially well under early planting-low stand density conditions and was characterized by high vegetative growth, late flowering, long EFT and high RP1. We propose a breeding strategy for both ideotypes based on seven indicators with high heritability (FF, HH, HNR, and LFB) or medium heritability (NVB, EFT, and RP1). I N T RO D U C T I O NThe cotton (Gossypium hirsutum) varieties commonly cropped in West and Central Africa, are sown at the onset of the rainy season and grown at a stand density ranging from 40 000 to 60 000 plants ha −1 . These varieties can thrive under extended but irregular rainfall conditions: they have a high flowering potential, long branches, long internodes and an indeterminate phenological cycle -the plants can quickly begin a new fruiting cycle after reaching cutout under suitable temperature and humidity conditions (Hau et al., 2001). Such varieties were considered well adapted to rainfed

Effective flowering time in Gossypium hirsutum cotton plants was studied with the aim of enhancing decision making on the best varieties to plant according to the planting date under rainfed cropping conditions. Trials were conducted at two sites in a cotton-growing area of Benin in 2002 and 2003. A split-split plot design with three replicates was used to compare 10 cotton varieties, with different growth cycle lengths and morphology, at three stand densities (42 000, 125 000, 167 000 plants ha −1 ) and two planting dates (standard planting in June and late planting). The flowering period was characterized by the mean first flower opening date (FF), which is an indicator of flowering earliness, and by the opening date of the last flower giving rise to a first-position boll on fruiting branches (LFP1). Effective flowering time (EFT) was calculated as the difference between LFP1 and FF. EFTs differed markedly in the 10 cotton varieties tested and this parameter could not be predicted on the basis of flowering earliness. Late planting and high planting rates delayed first-flower opening, accelerated last-boll development and reduced the effective flowering time. This latter factor should be taken into account in cotton breeding programmes so that varieties adapted to local rainfall constraints can be recommended to growers while also enhancing crop management sequences.

REMERCIEMENTS Ce travail a été sponsorisé par le Conseil Scientifique de l'Université de Parakou à qui nous adressons nos sincères remerciements. RESUMEAfin de comparer la diversité actuelle des écotypes de fonio à celle cultivée dix (10) ans plus tôt au Bénin, une enquête a été menée en 2013 dans la commune de Boukoumbé. Dans chacun des vingt (20) villages prospectés, un focus groupe d'une douzaine de producteurs a été à chaque fois enquêté. Cinq (5) à dix (10) producteurs sont ensuite entretenus individuellement à l'aide d'un questionnaire semi-structuré pour recueillir des informations sur les cultivars, leurs noms locaux, leurs principales caractéristiques, et la gestion des semences. Les résultats ont confirmé la diversité des appellations et ont permis de recenser cinq (5) cultivars différenciés par la précocité, la couleur des racèmes, les tailles de graines et de plantes. Les semences, transmises surtout de génération en génération, sont prélevées à 99% sur les récoltes précédentes. Près de 95% des enquêtés cultivent une seule variété à la fois. La plus forte diversité a été rencontrée chez les "Ditamaris" des villages de Boukoumbé-centre et Natta. "Iporapia" et "Takotapuaka" sont cultivés par toutes les ethnies. La diversité décrite dix (10) ans plus tôt dans la zone a été maintenue. Toutefois, les variétés de précocités extrêmes sont de moins en moins cultivées, et donc menacées de disparition. © 2015 International Formulae Group. All rights reserved.Mots clés : Espèce négligée, accession de fonio, Digitaliaspp., conservation in situ, amélioration variétale, Bénin.E. SEKLOKA et al. / Int. J. Biol. Chem. Sci. 9(5): 2446-2458, 2015 2447 Evolution of the diversity of fonio cultivars practiced in the commune of Boukoumbe in North-West of Benin ABSTRACTTo compare the current diversity of landraces of millet fonio to that cultivated ten (10) years ago in Benin, a survey was conducted in 2013 in the district of Boukoumbé. In each of the twenty (20) villages surveyed a focus group of a dozen producers was investigated every time. Then, five (5) to ten (10) producers are individually interviewed using a semi-structured questionnaire to collect information on cultivars, their local names, their main characteristics and seed management. The results confirmed the diversity of names and allowed to identify five cultivars differentiated by the earliness, color of racemes, sizes of seeds and plant height. Seeds, especially transmitted from generation to generation, are taken at 99% on the previous harvest. Nearly 95% of respondents grow only one variety at a time. The greatest diversity was encountered among the "Ditamaris" of villages in Boukoumbé center and Natta. "Iporapia" and "Takotapuaka" are cultivated by all ethnic groups. The diversity described ten (10) years earlier in the area has been maintained. However, the extreme precocity varieties are lesser and lesser grown, and therefore at risk of extinction.

In cotton (Gossypium hirsutum), it is hard to determine the exact date when reproductive growth ceases on the basis of field observations, as compared to more visible factors such as the onset of flowering or boll opening. It is, however, essential to characterize the growth cycle in order to determine what varieties are suitable for planting in different climatic and local cropping conditions. We estimated the end of the effective flowering period on the basis of the opening date of the last flower giving rise to a first-position boll on fruiting branches (LFP1), and propose a simple method for estimating this date. This study, conducted in 2002 and 2003 at Okpara, Benin, involved a comparison of six cotton varieties planted at two different dates (June and July). Plants were monitored to determine the dates when flowers opened at each position on fruiting branches. The LFP1 indicator made a clear distinction between varieties. This highly heritable trait, which was found to be closely correlated with other earliness criteria, could be used to characterize the length of the growth cycle in cotton varieties.