Agronomic & Solar utilization efficiencies of advanced rice lines in response to nitrogen application

Issue Date

4-2008

Abstract

The agronomic efficiency for nitrogen (AE) and solar utilization efficiency (SRUE) of 17 advanced rice lines, derived from crossing modern and elite genotypes under the UPLB Rainfed Rice Breeding Project, were evaluated under zero nitrogen (N) and 135 kg N/ha (from urea) levels during the 2006 wet season, rainfed conditions at the Central Experiment Station (CES), UPLB, College, Laguna. Results showed that out of the five-yielding lines, only C8321-B-1-1 had relatively higher AE (24.97 kg grain yield/kg N) than the check PSB Rc14 (22.48 kg grain yield/kg N). Most of the rice lines had higher (>20%) grain yield per cumulative solar radiation from vegetative to grain filling stages (GY/CSR) than the check under zero N. Under high N, only C8210-B-10-1 had significantly higher GY/CSR than the check. In terms of sink size per cumulative solar radiation from vegetative to reproductive stages (SS/CSR), all test lines except C8112-B-3-3-2 had SS/CSR of more than 20% than check under zero N. Under high N, the SS/CSR of the test lines did not differ with the check. C8112-B-4-1-1, C8231-B-1-1 and C8210-B-10-1 were high yielders under zero N. However, only C8231-B-1-1 had consistent high yields at high N. While line C8231-B-1-1 had high AE and SRUE, it has the capacity to produce higher grain yield and develop larger sink size per N fertilizer applied due to high number of panicles produced per unit area, while other yield components did not increase considerably at high N. This line has the potential to produce higher grain yields at high N provided that its grain filling process will be improved. There is still a need to calibrate AE and SRUE with the economics of fertilizer cost; efficiency of sink size production per unit cumulative solar radiations; and multi-location and season testing of the selected promising lines. At this point, we have shown the importance of AE and SRUE as additional parameters in selecting promising rice lines under varying N levels. The identification of high-yielding rice lines under zero N shown the possibility of developing rice cultivars that are productive under low N. This is especially relevant in view of the increasing price of N fertilizer, which in turn is due to the increasing price of fossil fuel oil.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463x

Volume

33

Issue

1

Page

81-96

Document Type

Article

Frequency

tri-quarterly

Physical Description

tables

Language

English

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