Reproductive barriers perform a vital role during speciation. Hybrid weakness, the poorer development of hybrids compared with their parents, hinders gene exchange between different species at the postzygotic stage. Here we show that two incompatible dominant loci (Hwi1 and Hwi2) involving three genes are likely to determine the high temperature-dependent expression of hybrid weakness in inters...

Although the discovery of aquaporins in plants has resulted in a paradigm shift in the understanding of plant water relations, the relationship between aquaporins and drought resistance still remains elusive. From an agronomic viewpoint, upland rice is traditionally considered as showing drought avoidance. In the investigation of different morphological and physiological responses of upland ric...

The virulence pattern of the isolates of Pyricularia grisea from commercial fields of the upland rice (Oryza sativa) cultivars ‘Primavera’ and ‘BRS Bonança’ was analyzed. A hundred and seventy monoconidial isolates of the pathogen virulent to ‘Primavera’ and 139 to ‘BRS Bonança’ collected from eight fields, during two years (2001-2003) were tested, under greenhouse conditions, on six newly rele...

Nitrate reductase inhibitor is usually found in the roots of rice plants (Oryza sativa L. cv MR7), but it was also produced in the shoots of aging plants. The inhibitor was inducible in the shoot of rice seedlings by dark, minus-nitrate or plus-ammonium treatments. There appears to be a general involvement of the inhibitor in the control of nitrate assimilation in the plant.

Brassinosteroids (BRs) are involved in many developmental processes and regulate many subsets of downstream genes throughout the plant kingdom. However, little is known about the BR signal transduction and response network in monocots. To identify novel BR-related genes in rice (Oryza sativa), we monitored the transcriptomic response of the brassinosteroid deficient1 (brd1) mutant, with a defec...

Oryza sativa or Asian cultivated rice is one of the major cereal grass species domesticated for human food use during the Neolithic. Domestication of this species from the wild grass Oryza rufipogon was accompanied by changes in several traits, including seed shattering, percent seed set, tillering, grain weight, and flowering time. Quantitative trait locus (QTL) mapping has identified three ge...

Rice (Oryza sativa) is India's pre-eminent crop, it is the most widely consumed staple food for a large part of the world's human population, especially in Asia. Moreover, the country has the biggest area under rice cultivation, as it is one of the principal food crops. India is one of the leading producers of this crop, with a production, productivity of 105.48 million tons and 2391 kg per hec...

Over the past 10 years, genomes of cultivated rice cultivars and their wild counterparts have been sequenced although most efforts are focused on genome assembly and annotation of two major cultivated rice (Oryza sativa L.) subspecies, 93-11 (indica) and Nipponbare (japonica). To integrate information from genome assemblies and annotations for better analysis and application, we now introduce a...

Hemoglobins (Hbs) corresponding to non-symbiotic (nsHb) and truncated (tHb) Hbs have been identified in rice ( Oryza). This review discusses the major findings from the current studies on rice Hbs. At the molecular level, a family of the nshb genes, consisting of hb1, hb2, hb3, hb4 and hb5, and a single copy of the thb gene exist in Oryza sativa var. indica and O. sativa var. japonica, Hb trans...

Despite its status as one of the world's major crops, linkage disequilibrium (LD) patterns have not been systematically characterized across the genome of Asian rice (Oryza sativa). Such information is critical to fully exploit the genome sequence for mapping complex traits using association techniques. Here we characterize LD in five 500-kb regions of the rice genome in three major cultivated ...