Q & A On Hybrid Rice

  • What is hybrid rice?

A Hybrid rice variety, also referred to as the F1, is the direct product of crossing two genetically different parents. In hybrids, the positive qualities of both parents are combined resulting in a phenomenon called “hybrid vigor” or “heterosis”, where young seedlings are highly and the mature plant has better reproductive characteristics. These factors result in higher yields than ordinary rice, also called inbreds.

Hybrid rice can raise farmers’ present yields by 15%. With proper management, farmers can raise yields by up to 240 cavans per hectare per season or  12 tons/ha/year.

  • How does hybrid rice differ from ordinary rice?

The rice plants we see in farmers’ fields today, including the more than 80 modern varieties released in the Philippines to date (except three) and all our traditional varieties are all inbred rice. Normally, each rice flower contains both male and female organs. This allows the plant to perpetuate or reproduce itself through self-pollination or inbreeding, hence the term inbred—without a man’s intervention. This means you can use the grains harvested from inbred rice as seeds for the next planting season.

A hybrid, on the other hand, is a product of two parents. Hence, new seeds must always be produced for planting the next season through cross-pollination. These seeds have variable sizes, may be discolored, partially filled, may have slightly opened hull, and generally lighter in weight compared with inbreds.

Two superior parent lines are crossed to get their best characteristics and combine them in the hybrid plant. Pollination is done by natural and chemical means. Seeds harvested from the hybrid plant cannot be used for replanting because hybrid vigor is lost resulting in lower yield and non-uniform crop stand.

  • What are HYVs, MRVs, Conventional Varieties, and NPT or Super Rice? How do they differ from hybrid rice?

HYVs (high-yielding varieties), MRVs (modern rice varieties), conventional varieties, and NPT (new plant type) or supper rice are terms used to differentiate these varieties from traditional varieties. Traditional varieties are tall and lodge easily. These are low-yielders, producing from 40-50 cavans/ha, and can be grown once a year since they take 56 months to mature. Most are photoperiodic. They have low tiller number, are often susceptible to insect pests and diseases, and the grains may shatter easily. Many, however, are aromatic and have good taste or eating quality.  

The terms HYVs, MRVs and conventional varieties all mean the same. These varieties are short or semi-dwarf; mature in about 4 months or less; are non-photoperiodic thus a second or third crop is possible; high yielding; resistant to insect pests and diseases; responsible to N; heavy-tillering; and well-suited to irrigated areas.

NPT or Super Rice is a variety designed for the future. Its target yield of 12 tons/ha will be achieved through a dramatic transformation of the rice plant architecture; less tillers; more grains per panicle; heavier grain weight per panicle; longer and extensive root system; more efficient use of water and nutrients; and greater resistance to insect pests and diseases. However, this is still being developed and improved.

Traditional varieties, HYVs, MRVs, conventional varieties, and NPTs or super rice of the future, however, share one thing in common: they are all self-pollinated unlike hybrid rice.

  • What is Hybrid Vigor?

This Phenomenon, that is unique to hybrid rices and also referred as ‘heterosis’, ix expressed during the early begetative and reproductive growth stages of hybrid rice plant. Young hybrid rice seedlings have faster root and leaf area development and better canopy development while the mature plant has increased total dry matter, greater number of spikelets per unit area, increased total weight of grains, and consequently, higher yields. This phenomenon is caused by the synergy among the positive characters of parental lines. It is important, therefore that good parents be used in hybrid rice seed production.

  • What hybrid rice varieties can farmers plant today?

There are three hybrid rice varieties approved by the National Seed Industry Council (NSIC): one released nationally, and two approved for location-specific release. Twenty-one promising hybrids are now under evaluation in the National Cooperative Tests (NCT)

PSB Rc26H or Magat. The Magat Hybrid bested PSB Tc4 by 17% and IR50 by 36% during the dry season. This is recommended primarily for Cagayan and Isabela, although is performed well in Camarines Sur, Iloilo, Cotabato, Laguna, Bohol, Masbate, Palawan, Capiz, Pangasinan, Agusan del Sur, and Zamboaga del Sur during the dry season.

Magat has an average yield of 5.6 t/ha, grows to a height of 88 cm and with a maturity of 110 days. Its higest yield was recorded in Maligaya, Nueva Ecija at 11.8 t/ha. It is resistant to blast and has intermediate reaction to bacterial leaf blight, rice tungro virus, yellow stem borer, green leafhopper and brown planthoppers. It has high amylose content, or is hard when cooked.

PSB Rc72H or Mestizo. It has a yield average of 6.3 t/ha during the dry season, grows to a height of 97 cm with growth duration of 123 days. A high yield of 11.4 t/ha was attained in Maligaya, Nueva Ecija during the 1997 DS. This medium maturing hybrid rice is recommended for nationwide planting. It has better eating quality with lower amylase, which means that is soft when cooked, and comparable to or better in eating quality than IR64. Its cooked rice has some aroma, that is preferred by most consumers.

PSB Rc76H or Panay. This hybrid gave superior performance, notably, in Camarines Sur, Laguna, and Bukidnon with an average yield of 5.2 t/ha during the dry season and 4.7 t/ha during the wet season (superiority over IR72 of 19% and 32%, respectively).

Maturity is early at 106 days and height is 102 dm. It is resistant to blast and has intermediate reaction to bacterial leaf blight and sheath blight. It has high amylose content, or is hard when cooked.

  • How Much Yield Increase Can Farmers Attain Using Hybrid Rice?

Results of large-scale on-farm hybrid rice technology demonstration trials conducted nationwide during 1998 dry season and 1999 dry and wet seasons indicate that, on average, a farmer can get an additional 779 kg palay/ha using the hybrid Magat and 1272 kg palay/ha using the hybrid Mestizo, as compared with planting the best and popular conventional varieties. These represent a yield increase of 15% and 25% for Magat and Mestizo hybrids, respectively. The highest yield obtained in these trials came from Mestizo at 12 t/ha in Cagayan and Bohol provinces.

  • How is Hybrid Rice Production Different from Farmers' Usual Practices?

Hybrid rice is grown much like ordinary rice except that it requires greater attention in seedling management. Seedling must be robust and their roots must be fully developed and should remain intact in order to minimize transplanting shock. This will allow the hybrid rice variety to fully express its “hybrid vigor” at the early vegetative growth, leading to increased number of spikelets. This means that hybrid rices have greater yield conversion using the same inputs as with the usual varieties.

The significant shifts from farmers’ usual practices include: (1) use of new seeds every planting season, that is, they cannot use their harvest as seeds; (2) use of only 20 kg seeds per hectare (farmers use from 80 to 120 kg of seeds per hectare); (3) application of 10-15 cavans farm wastes and organic materials in the seedbed to make the soil loose and friable. This is to facilitate seedling pulling while keeping roots of seedlings intact; (4) sparse seeding of 50 g/m2 or a total of 20 kg in 400 m2 seedbed; and (5) transplanting of 1-2 seedlings per hill (farmers transplant 3-5 seedlings per hill).

  • Can a Farmer Replant Seeds Harvested From Hybrid Rice?

No. While farmers growing ordinary rice varieties can use the grain they harvested from their existing crop as seeds for planting the following season, hybrid rice seed must be new every season. Otherwise, the resulting crop will not be uniform in height and in maturity. Furthermore, because of reduction in hybrid vigor, yields could decrease by about 20% and hence, be even lower that those obtainable from ordinary rice varieties.

To derive the benefits of high yield and uniform stand, the farmer must buy new seeds every season.

  • How Much Does it Cost to Grow Hybrid Rice?

There is minimal additional cost in using hybrid rice since farmers need only 20 kg seeds. At P120/kg, 20 kg seeds cost P2,400 or about the same as what farmers currently use – 3-4 cavans of 40 kg certified seeds at P700 per cavan, or P2,100 – P2,800. The additional cost will be on the use of organic fertilizer, gathering of organic wastes and incorporation in the seedbed, weeding of sparsely sown seedbed, extra care in seedling pulling and transplanting of 1-2 seedlings per hill, and replanting of missing hills.

Based on actual surveys, the average production cost incurred by hybrid rice farmers is P22,006 per season that was not significantly different from the P21,717 average cost of producing ordinary rice.

  • How Much Can the Farmer Profit From Hybrid Rice?

For commercial rice production. At a conservative yield of 5 tons per hectare, which is equivalent to 100 cavans of palay at 50 kg/cavan, a farmer gets a net return of P24,763/ha. Based on actual techno demo data, a hybrid rice farmer can get a net incremental benefit of not less than P6,000/ha/season, over the use of the best ordinary variety, even if he uses  40 kg/ha hybrid seeds. Any increase in yield level beyond 5 tons (up to 12 tons or 240 cavans/ha as has been clearly demonstrated in techno demo trials), would mean even higher profitability.

For seed production. Producing hybrid seeds offers new income opportunities for seed growers, rural farm hands, and women. Based on actual surveys, the average cost of producing hybrid seeds is P33,492/ha on-farm and P45,842 on research stations. If a yield of one-ton is attained, a hybrid seed producer can get a net profit of abut P92,000/ha/season. The higher the seed yield attained (a record yield of 3.0t/ha/season has been attained at PhilRice), the greater the profit.

At the hybrid seed price of P120/kg, a hybrid seed producer must get at least 232 kg seeds/ha and 2 t/ha male parent seed to recover total cost; a seed yield of 368 kg/ha to equal the income of commercial palay producers; and a seed yield of 580 kg/ha to equal the income form ordinary rice seed production.

  •  Can Hybrid Rice Lead us to Self-Sufficiency?

Hybrid rice is one of the key technologies that can make the country self-sufficient in rice. Our level of rice importation during the normal years is about 600,000 metric tons (mt). A minimum yield increase of one mt/ha through hybrid rice cultivation in the 800,000 ha irrigated rice area in the country can result in an additional rice production of 1.6 mt of palay (960,000 mt milled rice), easily making the country self-sufficient in rice.

  • What are the Thrusts of the DA and PhilRice on Hybrid Rice? 

The Department of Agriculture (DA) has made the development and use of hybrid rice technology an integral component of its rice production program. Hybrid rice research and development ( R & D), seed production, training, technology demonstration, and information dissemination activities initiated in 1998, are continuously being conducted in the 15 provinces for targeted hybrid rice cultivation (Ilocos Norte, Cagayan, Isabela, Nueva Ecija, Camarines Sur, Leyte, Maguindanao, South Cotabato, Lanao del Norte and Bukidnon).

PhilRice, the lead implementing agency for the hybrid rice program of the DA, on the other hand, established a Hybrid Rice R &D Program (HRP) in 1998, to continuously generate new and/or improve location-specific hybrid rice technologies. During its first full year (CY 1999) of implementation, the HRP put into operation 18 RD&E projects, with a total of 91 studies, implemented by 85 lead scientists and technical personnel. These included activities on germplasm conservation, varietal development, biotechnology, planting, nutrient, water and pest management, engineering and mechanization, socio-economics, and seed production. A PhilRice Hybrid Rice Center, based in San Mateo, Isabela was also established in 1998.

  • Who Will Produce Hybrid Seeds?

Private sector groups will produce, distribute, and market hybrid rice seeds. These include seed growers’ cooperatives, seed companies, interested NGOs and other organized groups, as well as accredited individual seed growers. PhilRice is paying special attention to the involvement of organized groups with contiguous seed production areas to be involved in hybrid rice production. This will reduce isolation problems, simplify seed certification, facilitate seed distribution and marketing, and allow seed growers to benefit from the economics of scale (e.g., loans, etc)

Selected members of the National Rice Seed Production Network (SeedNet) and the private sector will produce the foundation seeds of parental lines for use in hybrid seed production. PhilRice, IRRI and the University of the Philippines at Los Baños will produce nucleus and breeder seeds of released public hybrids. Nucleus, breeder, foundation, and certified seeds of proprietary hybrids such as Panay will be produced by the concerned seed companies.

The SeedNet presently has 95 active member (115 total) located in strategic rice growing areas of the country. PhilRice and IRRI have trained selected SeedNet personnel on parental hybrid seed production. For hybrid seed production, over 20 training courses were held since 1997, with over 800 participants coming from 24 provinces of the country. These included seed growers, seed certifying officers, seed inspectors, field technicians, provincial seed coordinators, and other key players in the rice sector.

  • What Countries Have Successfully Grown Hybrid Rice?

China grows hybrid rice in 17 million ha out of its total 33 million ha rice area. India grows hybrid rice in 150,000 ha while Vietnam cultivates 400,000 ha to hybrid rice. Hybrid rice technology helped China increase its rice production form 140 million tons in 1978 to 188 million tons in 1990. It accounts for 66% of China’s total production and 20 percent of the world’s total rice supply. Furthermore, hybrid rice technology has saved China more than 2 M ha of agricultural lands now being used of other purposes while preserving the environment. At least 17 other countries have initiated hybrid rice programs.

  • Who Supports The Philippines in its Hybrid Rice Program? 

The Philippines’ Hybrid Program is directly supported by the International Rice Research Institute(IRRI), Food and Agriculture Organization (FAO), of the United Nations, Asian Development Bank (ADB), the People’s Republic of China (PROC), and Rockefeller Foundation, Inc. (RF), and, indirectly, by the Japan International Cooperation Agency (JICA).

IRRI, based in Los Baños, Laguna, develops hybrid parent materials and promising hybrid rice lines that are entered into the national yield trials. It also helps train technical personnel from the national rice R & D network on both hybrid rice breeding and seed production and potential hybrid rice seed growers from the both public and private sectors.

The FAO is assisting the Philippine government develop its hybrid program by strengthening its manpower base. Under the Technical Cooperation Program (TCP) project entitled, “Strengthening the National Capacity for Hybrid Rice Development and Use”, for example, FAO assists the Philippine government strengthen its hybrid rice technical- and seed production personnel by providing in-country and foreign training opportunities, procurement of relevant equipment, and provision of consultancy services.

The ADB provinces support in the areas of technology generation, seed production, and technology promotion. Under a project coordinated by IRRI, the Philippines is a recipient of ADB funds that are used for nucleus and breeder seed production, refinement of seed production technologies, large-scale seed production, training, and information generation and dissemination.

Support form China is in the form of collaborative undertakings with noted Chinese hybrid rice institutions. PhilRice has implementation collaborative activities on breeding with Yunnan Agricultural University (YAU) since 1993, on varietal testing and seed production with the Jiangxi Academy of Agricultural Sciences (JAAS) since 1995 and the Guangxi Academy of Agricultural Sciences (GAAS) since 1997, and on breeding with Fujian Agricultural University (FAU) since 1998. Furthermore, in 1999, PhilRice has also forged a technical cooperation on hybrid rice technology with Yangzhou University (on breeding and biotechnology) and the Jiangxi Provincial Government (on hybrid rice seed production). In 1999, the DA also forged a technical cooperation agreement on hybrid rice with the Chinese Ministry of Agriculture to be implemented by PhilRice and the Hunan Provincial Seed Company. Informal collaborations have also been forged by PhilRice with the China National Rice Research Institute (CNRRI) and the South China Agricultural University (SCAU).

RF assistance comes through its support to PhilRice’s biotechnology program. For hybrid rice, biotechnology is being used to expedite the development of superior hybrids by widening parental genetic base, transferring important genes such as thermo-sensitive genetic male sterility for two-line hybrid breeding and resistances to insect pests and diseases. The biotechnological approaches being used to carry out these activities are molecular marker-assisted breeding, plant transformation in in-vitro culture. The ultimate goal would be to use biotechnology in developing, through plant apoximis, outstanding hybrids whose seeds can be replanted by resource-poor farmers just like inbred rice.

JICA support comes through its Technical Cooperation Project with PhilRice. Under this project, high yielding and high quality japonica rice from Japan are introduced to the Philippines to serve as germplasm material for breeding work. These materials are then crossed with Philippine indica varieties to produce high yielding, resistance, and good tasting rice. This activity increases the genetic base for the selection of possible parent materials for future hybrid breeding work.