Policy Support Needs of Hybrid Rice Technology in Asia - IRRI books

Table 1. Compact block frontline demonstrations conducted in India
(1999–2002).
State Hybrids No. of demos Yield
conducted advantage
(1 ha each) (kg ha -1 )
Maharashtra Sahyadri, PHB-71, 6201 651 950-2450
Karnataka KRH-2 550 700-1800
Andhra Pradesh DRRH-1, APHR-2, PHB-71 475 300-1150
West Bengal CNRH-3, KRH-2, PHB-71, 6201 410 500-1275
Tamil Nadu CORH-2, ADTRH- 0 400-900
Goa KRH-2, Sahyadri 00 900-2300
Uttaranchal PSD-1, PHB-7 96 600-1350
Uttar Pradesh NSD-2, PHB-71, 620 86 900-2450
Orissa DRRH-1, PHB-71, KRH-2 130 500-1300
Haryana, Bihar, Gujarat, PHB-71, DRRH-1, 6201 88 450-1475
M.P. Tripura and Delhi
Total
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Table 2. Productivity of inbreds and hybrids,
computed as yield in kg d -1 to maturity, taken from
IRRI Advanced Yield Trial data, 2002 dry season.
Genotype Maturity Yield Productivity
(d) (kg ha -1 ) (kg ha -1 d -1 )
PSBRc 28, chk 114.0 7038.0 61.7
PSBRc 52, chk 115.0 7724.0 67.2
Mestizo, chk 124.0 8901.0 71.8
IR79130H 112.0 7613.0 68.0
IR79131H 109.0 7770.0 71.3
IR79174H 114.0 8872.0 77.8
IR79187H 115.0 8407.0 73.1
their productivity per day was higher than those
of inbreds (Table 2). More recently, we have
found hybrid rices that are better adapted to
some unfavorable rice ecosystems such as rainfed
lowland shallow, moderately saline soils, and
aerobic rice environment (Virmani and Kumar
2004).
Agronomic management of rice
Since 1990, IRRI agronomists have established
that hybrid rices require a somewhat different
N management strategy compared with inbreds
to maximize their yield advantage. Their N
use efficiency was also found to be higher than
that of inbreds. More recent results also show
that, under water-limited conditions, hybrid
rices suffer less yield loss than do inbreds.
These results indicate an improved production
efficiency of rice hybrids. Therefore, strategic,
applied, and adaptive research on agronomic
management of hybrid rices is very important to
harness their yield potential in farmers’ fields.
Hybrid seed production technology
Hybrid rice seed production technology involves
two major steps: a) multiplication of the male
sterile line (female parent) and b) production
of hybrid (F 1 ) seeds. Seed yield obtained from a
male sterile line used in a hybrid seed production
plot is a function of a) yielding ability of the male
sterile line (extrapolated from the yielding ability
of its maintainer line), b) proportion of male
sterile line to pollen parent, and c) outcrossing
rate of the male sterile line. Improvement in any
of these components can help increase hybrid
rice seed yield.
Extensive research in China, IRRI, and other
countries has identified specific guidelines and
practices for hybrid rice seed production, which
are given in manuals (Yuan 1985, Virmani and
Sharma 1993) and research papers (Mao 1988).
Using these practices, hybrid seed yields from 0.7
to 4.0 t ha -1 (average 1.5 t ha -1 ) have been obtained
in the tropics. In the 2003 dry season, several
seed companies in India obtained seed yields
of 2-3 t ha -1 in Karim Nagar District in Andhra
Pradesh.
Economic viability
The availability of good-quality seed at a
reasonable price is crucial to the large-scale
adoption of hybrid technology in any crop.
Economic analyses conducted in India, Vietnam,
the Philippines, and Bangladesh have confirmed
the hybrids’ yield advantage of at least 1 t ha -1
over inbred check varieties grown by farmers
(Janaiah and Hossain 2000). Profitability,
however, depended on whether the farmers
received a price comparable with that of inbred
rice from the millers/traders. Some hybrid rice
varieties introduced to farmers in certain parts
of India fetched a 5-10% lower price, which