Boosting upland rice production through scientific discovery
Given limited arable lowland, some of the country’s upland areas are being cultivated for rice production. It is estimated that upland rice occupies close to 100,000 hectares with an average yield of 1.95 tons/ha.
Upland areas are rainfall dependent and are generally prone to drought because there is no field accumulation of water in the system. These areas are exposed to adverse factors such as water stress, hot and dry climatic conditions, and poor aerobic soils that have excesses of toxic elements, such as aluminum or manganese, or deficiencies of vital elements such as iron and phosphorus.
The deficiency of phosphorus (P) for instance, limits rice productivity and is mainly visible in drought environments because the mobility of P decreases sharply as the soil dries.
To address the deficiency of phosphorus in upland areas, a research project on “Genetic Improvement for Upland Rice through marker-assisted selection for Tolerance to Phosphorus Deficiency” was undertaken by the the Philippine Rice Research Institute (PhilRice).
The project aimed to develop P-tolerant lines or varieties under an upland condition that will produce higher yield than the current level of roughly 2 t/ha to at least 4 t/ ha grain yield.
Victoria Lapitan, supervising science research specialist of PhilRice Los Baños, said the application of phosphorus fertilizer and irrigation enhancements could be used to lessen the effect of low P availability and mitigate drought stress.
However, the lack of locally available P sources and the high cost of importing and transporting fertilizers prevent many resource-poor rice farmers from applying P.
The development of phosphorus uptake rice cultivars may be an attractive and cost effective approach to increasing rice yields where P deficiency is the major constraint.
Pup1 is a major quantitative trait locus (QTL) which confers tolerance of P deficiency in the soil.
Lapitan’s team has adopted the MAS method and the double haploid (DH) technique to fast track the development of rice varieties for an upland condition.
The researchers indicated that the use of MAS is advantageous in selecting for complex traits, pyramiding of multiple genes and in backcrossing, while in the DH approach, the system improves breeding efficiency by reducing the amount of time to develop elite lines.
The development of rice cultivars with enhanced P use efficiency coupled with higher P acquisition efficiency is an attractive and cost-effective strategy for a sustainable P management in upland farming.
Careful characterization and evaluation of these breeding lines in terms of their yield and agro-morphological performance will be continued in order to develop P-tolerant lines or rice varieties suitable for an upland condition.
Accroding to the research team, the combination of the MAS and DH techniques can be a powerful tool in the breeding program for upland rice and can be a faster way for success with much more certainty.
The rice genetic improvement project was funded under the Asian Food and Agriculture Cooperation Initiative (AFACI) which is being coordinated by the Bureau of Agricultural Research (BAR).
AFACI is an intergovernmental and multilateral cooperation body established through a memorandum of understanding signed among the member-countries on Nov. 3, 2009 in Korea.
It involves international collaboration for the development of sustainable agriculture and food technology to help economies deal with the changes in the agricultural environment.
Lapitan received the “Most Outstanding Principal Investigator” and “Outstanding Principal Investigator” awards in 2015 and 2016 for the implementation of the project under the AFACI rice program.