Exploring Optimal Cereal Crop Sequence Using Cultivated Land Utilization Index and Yield in Katihar District, India: A Sub Division Level Analysis

The present study attempts to identify the suitable crop sequences in an agriculturally productive district of Bihar, India. Rice-rice-vegetables, rice-maize-rice, rice-maize-maize, rice-maize-jute, rice-pulse-rice, rice-pulse-jute, rice-pulse-potato, and maize-maize-rice were found to be the suitable crop sequences in the area under study. Findings revealed that most of the blocks were found suitable for suggested crop sequences, while only two blocks (namely Balrampur and Barsoi) showed low potential in the rice-maize-rice sequence. Use of farm machinery, application of efficient farm inputs, and irrigation is required to maximize the yield and achieve long-term agricultural sustainability in this district.

Soil fertility and on-farm crop response to NPK and Zn fertilization in rice-rice cropping sequence of Lower Brahmaputra Valley Zone of Assam

Despite being a major source of livelihood, rice cultivation in the plains of the north-east region of India is under stress due to depletion of native nutrient reserves, emergence of multi-nutrient deficiencies and consequent decline in factor productivity of applied nutrients. With the aim to enhance productivity and to develop efficient fertilizer management strategies for the region, the authors discuss the status of post harvest soil properties and on-farm crop response to plant nutrients in rice-rice sequence under the climatic situation of Lower Brahmaputra Valley Zone of Assam. Results revealed that the recommended dose of NPK fertilizers along with 5 Kg ZnSO4 application not only increases the yield of rice-rice sequence but also enhances the post harvest fertility status of soil.

Sequence analysis of a rice BAC covering the syntenous barley Rpg1 region

In the course of map-based cloning of the barley stem rust resistance gene Rpg1, we identified a rice bacterial artificial chromosome (BAC) containing the Rpg1 flanking markers. Based on the excellent gene order colinearity between barley and rice in this region, we expected that this rice BAC would contain the barley Rpg1 homologue. In order to identify the putative rice homologue, we sequenced ca. 35 kb of the rice BAC at random and then an additional 33 kb of contiguous sequence between the two most closely spaced Rpg1 flanking markers. Sequence analysis revealed a total of 15 putative genes, 5 within the 33-kb contiguous region. A rice Rpg1 homologue was not identified, although a gene encoding a hypothetical polypeptide with similarity to a membrane protein could not be eliminated as a candidate. Surprisingly, four of the genes identified in the 33-kb contiguous rice sequence showed a high degree of similarity with genes on Arabidopsis chromosome 4. The genome regions harboring these genes showed some relatedness, but many rearrangements were also evident. These data suggest that some genes have remained linked even over the long evolutionary separation of Arabidopsis and rice, as has also been reported for mammals and invertebrates.Key words: genes, genome, rice, synteny, sequence.

Fate of fertilizer zinc in a black soil (Vertisol)

Rice is the major food crop grown on black soils of southern India and these soils have problems of high zinc fixation due to high clay content, high pH and dominance of smectite minerals causing zinc deficiency problems. The addition of zinc fertilizers to these soils has often been ineffective as the element is transformed to unavailable forms particularly under flooded rice conditions. Studies on the distribution of fertilizer zinc among different pools of soil zinc (Viets, 1962) could be useful in formulating methods of zinc application for higher efficiency of utilization. An attempt was therefore made to study the transformations of added zinc in soils in field experiments conducted in a rice-rice sequence involving the use of 65Zn as a tracer.