Evaluation of Different Substrates Compositions for Acclimatization of Tissue Culture Taro Plantlets in a Propagator

Taro is cultivated in most Regions of Cameroon and it is affected by taro leaf blight disease since 2010 which has decreased its production. Lack of disease-free planting materials has been a main problem to farmers. This study was carried out at International Institute of Tropical Agriculture (IITA) Yaounde and Institute of Agricultural Research for Development (IRAD) Bambui to assess different substrates for acclimatization of tissue culture taro plantlets in apropagator. No information is available on acclimatization of Cameroonian taro plantlets in different substrates. Taro plantlets from tissue culture were acclimatised in a propagator for six weeks under different substrates, the first substrate consisted of sterile three parts of soil and one part of river sand mixed together (3:1), the second substrate consisted of sterile two parts of soil and two parts of river sand mixed together (2:2), the third substrate consisted of sterile two parts of soil, one part of rice husk and one part of river sand mixed together (2:1:1) and the fourth substrate consisted of sterile one part of soil and three parts of river sand mixed together (1:3). After acclimatisation of the different taroplantlets (Dark green petiole with small leaves (L1), Red petiole with small leaves (L2), Light green petiole with large leaves (L3) and Light green petiole with small leaves (L4) in these four substrates, it was observed that the best growth rate of plant was recorded on substrate sand + soil (1:3). The other substrates showed moderate growth of plants. Substrate sand + soil (1:3) can be recommended for acclimatization of Cameroonian taro plantlets.

Effect of agar concentration in media on green plantlet regeneration frequency in rice anther culture

We studied the effect of agar concentration inmedia on callus induction rate and green plant-let regeneration frequency in rice.Materialswere Fgeneration of indica/indica or indica/japonica,which were 96E76(Hei’e/Zhaiye- qing 8),96E80[(IR 24/Guanglu＇ai 4//Zhongnan’ai)/Yifengzao],96E86(Zhong- munong 9/Zhaiyeqing 8).The induction mediaused was M8+2mg/L 2,4-D,and agar con-centrations were 0.6％,0.8％,and 1.0％,respectively.Regeneration media was MS+2mg/L KT+0.5mg/L IAA+0.5mg/LNAA,and agar concentrations were 0.6％ and1.0％.Results indicated that the calli induc-

Sterile Germination of Dendrobium chrysotoxum Seeds and Rapid Propagation of Its Plantlets

[Objective] This study was to produce plant seeds on a large scale via sterile germination of the capsules of Dendrobium chrysotoxum and rapid propagation technique.[Method] A large amount of protocorm-like bodies produced from the sterile germination of D.chrysotoxum capsules,were transferred to four different kinds of bud induction media to obtain the optimal media suitable for plantlet differentiation and growth;and then with N6 as basic medium,1.0,1.5 and 2.0 mg/L of NAA and IAA were tested to obtain the optimal media suitable for rooting.[Results] On the medium of MS appended with 1 mg/L 6-BA ＋10% banana puree ＋ 20 g/L sucrose ＋6 g/L agar＋1 g/L AC,seed germination rate was up to 90%.The optimal medium for differentiation of D.chrysotoxum protocorm-like bodies was N6＋ 2 mg/L NAA ＋ 0.5 mg/L 6-BA ＋10% banana puree ＋ 20 g/L sucrose ＋ 0.5 g/L peptone ＋ 5.8 g/L agar ＋0.5 g/L AC,grown from which the plantlets were even and orderly in height;and the optimal medium for rooting was N6＋1.5 mg/L NAA ＋10% banana puree ＋ 20 g/L sucrose ＋ 5.8 g/L agar ＋1 g/L AC,grown from which the plantlets developed more,robust and orderly roots,and their leaves were in dark green color.[Conclusion] Our results provided reference for the rapid propagation of D.chrysotoxum.