Genetics of resistance of rice cultivar ARC10550 to Bangladesh brown pianthopper teletype

Resistance to brown planthopper in rice cultivar ARC 10550 was found to be governed by a single recessive gene which was designatedbph 5. It conveys resistance to brown planthopper populations in South Asia but not to the populations in East and Southeast Asia. This gene segregated independently of four other known genes for brown planthopper resistance. It should be possible to combine this gene with any of the other four genes to develop rice cultivars with a broad spectrum of resistance. [1]

RFLP mapping of genes conferring complete and partial resistance to blast in a durably resistant rice cultivar.

Moroberekan, a japonica rice cultivar with durable resistance to blast disease in Asia, was crossed to the highly susceptible indica cultivar, CO39, and 281 F7 recombinant inbred (RI) lines were produced by single seed descent. The population was evaluated for blast resistance in the greenhouse and the field, and was analyzed with 127 restriction fragment length polymorphism (RFLP) markers. Two dominant loci associated with qualitative resistance to five isolates of the fungus were tentatively named Pi-5(t) and Pi-7(t). They were mapped on chromosomes 4 and 11, respectively. To identify quantitative trait loci (QTLs) affecting partial resistance, RI lines were inoculated with isolate PO6-6 of Pyricularia oryzae in polycyclic tests. Ten chromosomal segments were found to be associated with effects on lesion number (P < 0.0001 and LOD > 6.0). Three of the markers associated with QTLs for partial resistance had been reported to be linked to complete blast resistance in previous studies. QTLs identified in greenhouse tests were good predictors of blast resistance at two field sites. This study illustrates the usefulness of RI lines for mapping a complex trait such as blast resistance and suggests that durable resistance in the traditional variety, Moroberekan, involves a complex of genes associated with both partial and complete resistance. [2]

Rice cultivar evaluation for phosphorus use efficiency

Phosphorus deficiency is one of the most growth-limiting factors in acid soils in various parts of the world. The objective of this study was to screen 25 rice cultivars (Oryza sativa L.) at low, medium, and high levels of soil P. Number of tillers, root length, plant height, root dry weight and shoot dry weight were related to tissue P concentrations, P uptake and P-use efficiency. Shoot weight was found to be the plant parameter most sensitive to P deficiency. Significant cultivar differences in P use efficiency were found. Phosphorus use efficiency was higher in roots than shoots and decreased with increasing levels of soil P. Positive correlations were found among growth parameters such as plant height, tillers, root and shoot weight, and P content of roots and shoots. These results indicate selection of rice cultivars for satisfactory performance under low P availability can be carried out using shoot and root dry weight as criteria. [3]

Performance of Legendary Local Fragrant Rice in Bangladesh

Conventional cooking is just enough for rice hunger but, aromatic rice adds special dimension when cooked for its characteristic distinct flavor. Investigation aimed to evaluate the performance of most preferable aromatic rice cultivars in Bangladesh. Five cultivars differ significantly among them for physical, physico-chemical and cooking qualities, respectively. With the comparison of this quality Radhunipagol perform better over Basmati (checked). The use of these rice cultivars may improve the socio-economic condition for its excellent grain quality characteristics, preference and overall acceptability than that of Katarivug, Sarnalota and Tulshimala. [4]

Rice Cultivar Production and Seed Overwinter Potential in Upstate Missouri

Climate change and opportunities for pharmaceutical rice (Oryza sativa L.) production in the U.S. may affect future production opportunities. Field research in 2005–2007 at Bethel (39º56’N, 92º3’W) and in 2005 at Novelty (40º01’N, 92º11’W) evaluated the production potential of rice cultivars (10 conventional or hybrid varieties), overwinter seed survival, and the effects of weeds on yield in upstate Missouri. Grain yields ranged from 3,880 kg ha^-1 (Ilpumbyeo) to 10,540 kg ha^-1 (Trenase). M103, M202 and XP723 yielded similarly to Trenase. Late-maturing cultivars had the greatest risk of yield loss due to frost damage. Weed interference [barnyard grass (Echinochloa crus-galli L.), fall panicum (Panicum dichotomiflorum Michx.), giant foxtail (Setaria faberi Herrm.), common cocklebur (Xanthium strumarium L.), and common waterhemp (Amaranthus rudis Sauer)] reduced grain yields of Cocodrie 35%, emergence by 4%, plant height by 21%, and head number by 21%. In fall 2005 and 2006, rice seed produced during the previous year was seeded on the soil surface, with vertebrate exclusion, and vertebrate plus invertebrate exclusion. Viable seed overwintered with 0.06 to more than 12% emergence the following spring. The yield potential of rice in upstate Missouri looks promising, but correct cultivar selection and weed control are essential for successful production.. [5]

Reference

[1] Khush, G.S., Karim, A.R. and Angeles, E.R., 1985. Genetics of resistance of rice cultivar ARC10550 to Bangladesh brown pianthopper teletype. Journal of Genetics, 64(2), pp.121-125.

[2] Wang, G.L., Mackill, D.J., Bonman, J.M., McCouch, S.R., Champoux, M.C. and Nelson, R.J., 1994. RFLP mapping of genes conferring complete and partial resistance to blast in a durably resistant rice cultivar. Genetics, 136(4), pp.1421-1434.

[3] Fageria, N.K., Wright, R.J. and Baligar, V.C., 1988. Rice cultivar evaluation for phosphorus use efficiency. Plant and Soil, 111(1), pp.105-109. [4] Chakraborty, R., Roy, T.S., Quamruzzaman, M., Bandopaddhya, N. and Rasul, M.G., 2016. Performance of legendary local fragrant rice in bangladesh. Journal of Agriculture and Ecology Research International, pp.1-7.

[5] Sandler, L., Nelson, K.A. and Smoot, R.L., 2012. Rice cultivar production and seed overwinter potential in upstate Missouri. Journal of Experimental Agriculture International, pp.426-441.