Rice varieties

X. Yang, V. Romheld, and H. Marschner, Effect of bicarbonate on root growth and accumulation of organic acids in Zn-ineffcient and Zn-efficient rice varieties (Oryza sativa L.) Plan Soil I64 (1994). 

Figure 2. Methane emissions from standard-stature, conventional rice varieties, such as "Taggart" (top left) and "Wells" (top right), and hybrids varieties, such as "CLXL745" (bottom) have recently been studied in the field at the Rice Research and Extension Center near Stuttgart, AR. Photographs taken by K. Brye.

Lindau CW, Bollich PK, DeLaune RD. Effect of rice variety on methane emission from Louisiana rice. Agric. Ecosys. Environ. 1995 54 109-114. 

Ma K, Qiu Q, Lu Y. Microbial mechanism for rice variety control on methane emission from rice field soil. Global Change Biol. 2010 16 3085-3095. 

Shuman L.M., Wang J. Effect of rice variety on zinc, cadmium, iron and manganese content in rhizosphere and non-rhizosphere soils fractions. Commun. Soil Sci Plant Anal 1997 28 23-36. 

Iron toxicity is a syndrome of disorders associated with large concentrations of Fe + in the soil solution. It is only found in flooded soils. A wide range of concentrations produce the symptoms, from 1000 to only 10mgL in soils with poor nutrient status—especially of P or K—or with respiration inhibitors such as H2S. There are large differences in tolerance between rice varieties. The effects include internal damage of tissues due to excessive uptake of Fe + impaired nutrient uptake, especially of P, K, Ca and Mg and increased diseases associated with imbalanced nutrition, such as brown leaf spot (caused by Helminthospo-rium oryzae), sheath blight (caused by Rhizoctonia solani) and blast (caused by Pyricularia oryzae). 

While allelopathy is not covered in this chapter, excellent weed control can be achieved at reduced herbicide rate when used in conjunction with allelopathic rice varieties. Therefore, selection of highly allelopathic crop varieties, either through traditional breeding or using genetic engineering techniques, may also provide novel and low input approaches to weed control. 

Lou, Y. and Cheng, J. (1996). Behavioral responses of Anagrus nilaparvatae Pang et Wang to the volatiles of rice varieties. Entomological Journal of East China 5 60-64. 

Hassan S. M., Aidy I.R., Bastawisi A.O. Allelopathic potential of rice varieties against major weeds in Egypt. Paper presented at annual meeting of Weed Science Society of America. Seattle, Washington, USA. 1995. 

Kong, C.H., Xu, X.H., Hu, F., Cheng, X.H., Lin, B., Tan, Z.W. Using specific secondary metabolite as marker to evaluate allelopathic potential of rice variety and individual plant. Chin Sci Bull 2002b 47 839-843. 

We therefore came up with a creative method for licensing. UC Davis negotiated option agreements to license the Xan gene to two companies, Monsanto and Pioneer. As part of the negotiation, the companies were excluded from developing rice varieties in less developed countries. That way, noncommercial researchers, such as those in... 

Rice varieties are distinguished by their amylose content. There are two basic types common and waxy. Waxy rice has an amylose content of 0-2%. Common or regular rice varieties are referred to as having amylose contents that are low (9-20%), medium (20-25%) or high (>25%) amylose. The availability of waxy rice is usually limited and large requirements for waxy rice are contracted in advance to ensure a supply. 

Depending on the relative amylopectimamylose ratio found in the rice, the starch can exhibit a variety of gelatinized textures and strengths, as well as resistance to acid. Overall, there are several basic factors that affect starch performance. These factors, which include rice variety, protein content, method of starch production and modification, are described below. 

Prepared from US rice varieties by the mechanical method... 

Africa. Asian cultivated rice evolved into three eco-geographical types, Indica, Japonica, and Javanica. It is estimated that about 120,000 distinct rice varieties exist in the world, which differ from one another in terms of growth duration, endosperm traits, level of tolerance to coldness, or other abiotic stresses (e.g., drought, salinity, and submergence), as well as resistance to diseases and pests. In some countries, varieties are classified also according to the season in which they grow [1]. 

---