Salinity is one of the most serious problems in rice cultivation. Salinity drastically reduced plant growth and yield, especially at seedling stage. Several rice genotypes have been produced, but their tolerance to salinity has not yet been evaluated. The study aimed to evaluate salinity tolerance of rice genotypes at seedling stage. The glasshouse experiment was conducted at Cimanggu Experimental Station, Bogor, from April to May 2013. Thirteen rice genotypes and two check varieties, namely Pokkali (salt tolerant) and IR29 (salt sensitive) were tested at seedling stage. The experiment was arranged in a randomized complete block design with three replications and two factors, namely the levels of NaCl (0 and 120 mM) and 13 genotypes of rice. Rice seedlings were grown in the nutrient culture (hydroponic) supplemented with NaCl at different levels. The growth and salinity injury levels of the genotypes were recorded periodically. The results showed that salinity level of 120 mM NaCl reduced seedling growth of all rice genotypes, but the tolerant ones were survived after 14 days or until the sensitive check variety died. Based on the visual injury symptoms on the leaves, five genotypes, i.e. Dendang, Inpara 5, Inpari 29, IR77674-3B-8-2-2-14-4-AJY2, and IR81493-BBB-6-B-2-1-2 were tolerant to 120 mM salinity level, while Inpara 4 was comparable to salt sensitive IR29. Hence, Inpara 4 could be used as a salinity sensitive genotype for future research of testing tolerant variety. Further evaluation is needed to confirm their salinity tolerance under field conditions.

<p>ABSTRACT<br /><br />Haploid breeding through anther culture allows shortening of the breeding cycle and production of homozygous lines from a segregating population in the immediate generation. This technique has been used for crop improvement especially in rice. The objective of this research was to determine regeneration ability of twelve F1s, derived from reciprocal crossing between high yielding rice variety and rice tolerance to salinity, through anther culture. Completely randomized design with 20 replications was used in this research. Medium for callus induction was based on N6 medium + 2.0 mg NAA L-1 + 0.5 mg kinetin L-1 + 1 mM putrescine, while regeneration medium was based on MS + 0.5 mg NAA L-1 + 2.0 mg kinetin L-1 + 1 mM putrescine. Rooting were done in MS medium + 0.5 mg IBA L-1 + 1 mM putrescine. The result indicated that F1 derived from IR77674/Inpari 29 (3.1% green plants/total anther) was the most responsive genotypes in rice anther culture (high anther culture ability). After greenhouse grow out 125 putative double haploid plants were obtained (41.5% from total acclimated green plantlets).  <br /><br />Keywords: double haploid, green planlets, indica rice, salt tolerance <br /><br /></p>

ABSTRACT. Yield Stability of Promising Lowland

Anther culture is an important biotechnological tool. By rice anther culture homozygous pure lines in the form of doubled haploid (DH) plants can be produced within a year as compared to the long inbreeding method, which might take 8-10 years. Application of anther culture technique in breeding and genetics research is limited due to the very low regeneration frequency of anthers of rice in general, and indica cultivars in particular. Therefore, the successful use of the technique depends on the adequate production of DH plants for selection and field evaluation. Effect of various concentrations of sucrose in callus induction media was investigated on callus induction and regeneration of green plantlets from anther culture of several F1s derived from indica x indica crosses. Cold pretreated anthers of five genotype of anther donor plants (F1s) at 5 °C for 8 days were cultured on N6 callus induction medium containing sucrose at a concentration of 6.0%, 6.5%, and 7.0%. Results revealed that all genotypes showed similar response to callus induction, but a significantly different responses to plant regeneration depended on sucrose level in the callus induction media. Two genotypes, i.e. IR78788 / Inpara 5 and Dendang/Inpari 30 only regenerated albino plantlets. In this experiment, 6.5% sucrose compared to two other sucrose treatments was suitable for inducing high frequency callus induction and high green plant regeneration in all genotypes. The high concentration of sucrose (7.0%) in the culture medium not only resulted in a decrease in the number and percentage of callus formation but also decreased the regeneration of green plantlets.

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Ciherang is the most extensively planted rice variety in the Indonesia. Ciherang was released as a rice variety in 2000 and successfully replaced IR 64 as the most dominant variety. The wide adoption of Ciherang is because of its acceptable to farmers’ preferences including high yield, resistance to major diseases and good grain quality. Recently, Ciherang become vulnerable to pest and diseases and get low yield due to more occurrence the abiotic stress. The Rice breeding program to develop the Ciherang reborn has been conducted in Indonesian Center for Rice Research. The research aimed to select lines based on yield, morphological performance, and resistant to main pest and diseases for next evaluation of a multilocation yield trial for releasing variety. The materials used were 56 rice genotypes that evaluated yield, agronomic characters, and evaluated to brown planthopper and bacterial left blight. Ten promising lines was selected, derivative from Ciherang or similar ideotype with Ciherang, high yielding, more resistant to main pest and diseases than Ciherang. These promising lines was evaluated in multilocation yield trials for releasing variety.

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