Genes controlling hormone levels have been used to increase grain yields in wheat (Triticum aestivum) and rice (Oryza sativa). We created transgenic rice plants expressing maize (Zea mays), rice, or Arabidopsis thaliana genes encoding sterol C-22 hydroxylases that control brassinosteroid (BR) hormone levels using a promoter that is active in only the stems, leaves, and roots. The transgenic plants produced more tillers and more seed than wild-type plants. The seed were heavier as well, especially the seed at the bases of the spikes that fill the least. These phenotypic changes brought about 15 to 44% increases in grain yield per plant relative to wild-type plants in greenhouse and field trials. Expression of the Arabidopsis C-22 hydroxylase in the embryos or endosperms themselves had no apparent effect on seed weight. These results suggested that BRs stimulate the flow of assimilate from the source to the sink. Microarray and photosynthesis analysis of transgenic plants revealed evidence of enhanced CO 2 assimilation, enlarged glucose pools in the flag leaves, and increased assimilation of glucose to starch in the seed. These results further suggested that BRs stimulate the flow of assimilate. Plants have not been bred directly for seed filling traits, suggesting that genes that control seed filling could be used to further increase grain yield in crop plants.

To develop an FLP-FRT recombination system- (derived from 2 mu plasmid of Saccharomyces cerevisiae) based marker gene removal application for rice, we introduced the gene for FLP recombinase, under the control of the maize ubiquitin-1 promoter, into the rice genome. FLP activity was monitored in callus and regenerated plants by an assay based on the deletion of the FRT-flanked DNA fragment, leading to the activation of the beta-glucuronidase gene. FLP activity was detected both in the callus and leaves of some of the transgenic lines. Based on our comparison of the recombination efficiency of the FLP-FRT system expressed in the transgenic lines with that of the widely used Cre-lox system (derived from bacteriophage P1), we suggest that the FLP-FRT system is a useful tool for the genetic manipulation of rice.

<p>Even though fourteen improved varieties of small cardamom have been released in India so far, many of the farmers in the<br />traditional cardamom tracts still use farmer selected landraces as planting material and hence the importance of landraces is not<br />questionable. Four new landraces of small cardamom identified from Idukki district of Kerala State of India namely Pulari,<br />Pappalu, Kalarikkal Bold and Arjun were evaluated along with Njallani Green Gold (popular landrace) and ICRI-2 (improved<br />variety released by Indian Cardamom Research Institute) for growth, yield and quality characters. Eight growth characters, eight<br />yield characters and eleven quality characters were analyzed for the purpose and all of them except two yield characters showed<br />statistically significant variation indicating the occurrence of significant genotypic difference between these landraces. A comparative<br />analysis of overall performance of the four landraces was also carried out and the results showed that Pappalu, Kalarikkal Bold<br />and Pulari performed significantly superior to Njallani Green Gold and ICRI-2, the controls. Pappalu showed 132.22 per cent<br />increase in yield over Njallani Green Gold and 158.02 per cent over ICRI-2. The cumulative performance indices of all the new<br />landraces were worked out and the landrace Pappalu had the highest performance index of 30.06 followed by Kalarikkal Bold<br />(27.45), Arjun (25.57) and Pulari (24.14). All the four new landraces have been found to be superior to ICRI-2 while Pappalu,<br />Kalarikkal Bold and Pulari showed superiority over Njallani Green Gold, under preliminary evaluation.</p>

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