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-

Effect of desiccation on regeneration frequency of green plantlets and some biochemical properties of calli of wild rice

Wild rice is an important resource of usefulgenes to rice breeders. However, low regener-ation frequency is an obstacle to use the valu-able genes. We used desiccation to improve theregeneration frequency and studied the bio-chemical changes of calli of wild rice after des-iccation.Materials used in this experiment werewild species O. rufipogon, O. meyeriana, O.alta, and O. brachyantha. Young panicles(0.1-0. 5 cm in length of the inflorescence)

The Influence of Endogenous Hormones on Culture Capability of Different Explants in Rice

The endogenous hormones (EHs) content of different explants (anther, young panicle, young embryo and mature embryo) and calli with different culture capability were analyzed by means of high performance liquid chromatography (HPLC). The results showed that the contents and ratio of endogenous hormones were one of the key factors affecting callus induction frequencies (CIF) and green plantlet differentiation frequencies (GPDF). The influence of endogenous hormones of different explants on CIF represented as: Zoatin ribosile (ZR) showed negative effect, indole-3-acetic acid (IAA) did positive effect, and gibberellic acid (GA) did negative effect except for mature embryos. The influence of endogenous hormones on green plantlet differentiation frequency (GPDF) showed: IAA and GA were negative effect; abscisic acid (ABA) and zeatin+ zeatin riboside (Z+ZR) were positive effect. The mixture ratio of endogenous hormones played a role on CIF and GPDF. IAA/Z+ZR had a positive effect on CIF, and there was a notable positive correlation between Z+ZR/ IAA and GPDF, so was between ABA/IAA and GPDF.

Tissue Culture Responses from Different Explants of Rice

Different culture explants, including anther, young panicle, young embryo, and mature embryo, from 19 rice varieties were used for callus induction and green plantlet differentiation. The culture efficiency differed significantly among the four types of explants, and varied from genotype to genotype. Callus induction frequency presented significantly positive correlation each between anther and young panicle, anther and mature embryo, and young panicle and young embryo. Green plantlet differentiation showed no relationship between different types of explants. In addition, no relationship was found between callus induction frequency and green plantlet differentiation frequency.