Dr. P.Raghuveer Rao National conference of plant physiology-2013 on “current trends in plant biology research” December 13-16,2013,Junagadh,Gujarat. Dr. P.Raghuveer Rao Senior Scientist Plant Physiology Directorate of rice research Rajendranagar-hyderabad-500 030

Research Activities at DRR Lead Research Externally Funded Projects AICIRIP-pl.physiology

Major advances have occurred in rice production due to adoption of green revolution technology. Between 1966 and 2000, the population of densely populated low income countries grew by 90% but rice production increased by 130% from 257 million tons in 1966 to 600 million tons in 2000. However, the population of rice consuming countries continues to grow and it is estimated that we will have to produce more rice in 2030. This increased demand will have to be met from less land, with less water, less labour and fewer chemicals. To meet the challenge of producing more rice from suitable lands we need rice varieties with higher yield potential and greater yield stability. Various strategies for increasing the rice yield potential being employed include: (1) conventional hybridization and selection procedures, (2) ideotype breeding, (3) hybrid breeding, (4) wide hybridization and (5) genetic engineering. Various conventional and biotechnology approach are being employed to develop durable resistance to diseases and insect and for tolerance to abiotic stresses. The availability of the rice genome sequence will now permit identification of the function of each of 60,000 rice genes through functional genomics. Once the function of a gene is identified, it will be possible to develop new rice varieties by introduction of the gene through traditional breeding in combination with marker aided selection or direct engineering of genes into rice varieties. What it will take to feed 5.0 billion rice consumers in 2030

Ideotype breeding Ideotype breeding aimed at modifying the plant architecture is a time tested strategy to achieve increases in yield potential. As an example selection for short stature cereals such as wheat, rice and sorghum resulted in doubling of yield potential. Introduction of sd1 gene for short stature into rice led to improvement in harvest index from 0.3to 0.5 and increases in biomass production. To increase the yield potential of rice further, anew plant type was conceptualized in 1988. Modern semi-dwarf rices produce a larger number of un productive tillers and excessive leaf area which cause mutual shading and reduce canopy photosynthesis and sink size, especially when they are grown under direct sowing conditions. To increase the yield potential of these semi-dwarf rices furthermore scientists proposed further modifications of plant architecture with following characteristics: • Low tillering (9–10 tillers when transplanted) • No unproductive tillers • 200–250 grains per panicle • Dark green and erect leaves • Vigorous and deep root system Breeding efforts to develop ‘‘New Plant Type’’(NPT) were initiated in 1990. The objective was to develop improved germplasm with 15–20% higher yield than that of existing high yielding varieties. Numerous breeding lines with desired ideotype were developed (Khush, 1995) and were shared with national rice improvement programs. ThreeNPT lines have been released in China and one in Indonesia. Other NARS (National Agricultural Research Systems) are evaluating and further improving the NPT lines.

Increasing the Yield Potential of Rice Various strategies for increasing the yield potential of rice includes conventional hybridization and selection procedures, Ideotype breeding, Heterosis breeding, Wide hybridization, Genetic engineering.   

ILS Introgressed lines Germplasm Tropical Jopanicas HYV/Hybrids 1 13- 7 MSP-1 19 E- 2710 34 TJP- 20 59 NDR 359 2 S-40 MSP-2 20 E- 2729 35 TJP- 138 60 PHB- 71 3 50- 13 MSP-3 21 E- 2857 36 TJP- 139 61 DRRH- 3 4 248(S) MSP-4 22 E- 2875 37 TJP- 142 62 Dhana Rasi 5 S- 40 MSP-5 23 E- 2940 38 TJP- 150 63 KRH- 2 6 RPHR- 517 MSP-6 24 E- 3067 39 TJP- 157 64 Rasi 7 RPHR- 1005 MSP-7 25 E- 3082 42 TJP- 197 65 Jaya 8 RPHR- 1096 MSP-8 26 E- 3118 43 TJP- 198 66 Vijetha 9 IBL- 57 MSP-9 27 E- 3127 45 TJP- 4 67 Jarva 10 Swarna (Check) MSP-10 28 E- 3138 47 TJP- 34 68 Sampada   11 MSP-11 29 E- 3173 50 TJP- 27 69 PA 6444 12 MSP-12 30 E- 3287 51 TJP- 82 70 MTU 1010 13 MSP-13 31 E- 3321 52 TJP- 58 71 Akhanphou 14 MSP-14 32 E- 3324 54 TJP- 229 72 IR 72 15 MSP-15 33 E- 3325 56 TJP- 224 16 MSP-16 57 TJP- 5 17 MSP-17 18 MSP-18 KMR3 x O.rufipogan Swarna x O.nivara Restorers/ R-lines

average of all harvested areas in China Average annual yield of rice per unit land area in China. Each data point is the average of all harvested areas in China

Variation in leaf photosynthetic traits in divergent rice genotypes under field condition S.No. Parameter df MSS F ProbF Range 1 Rate of Photosynthesis ( PN ) 106 4.79 19.94 2.583E-40** 32.4 - 6.98 2 Stomatal conductance (gs) 0.10 8.26 1.918E-23** 1.00 - 0.133 3 Intercellular CO2 Concentration 1178.03 4.51 1.225E-13** 314.4 - 218.5 4 Transpiration Rate (E) 16.21 15.12 8.67E-35** 14.5 - 3.8 5 Ci/Ca ratio 0.01 4.33 4.581E-13** 0.862 - 0.593 6 Water Use Eficiency (PN/E) 0.39 8.75 1.80E-24** 4.15 - 1.41 7 Intrinsic Water Use Efficiency) 416.58 4.49 1.49E-13** 86.9 - 24.5 8 Carboxylation efficiency 0.00 16.00 6.66E-36** 0.126 - 0.0254

Variation in Photosynthetic efficiency [µmol (CO2)m-2s-1 ] in different groups of rice Mean Range df MSS F ProbF AVT-1-ME (16) 23.74 26.92 - 21.70 14 5.17 4.128 0.0047*** Hybrids (8) 21.27 25.53 - 14.71 6 25.64 4.573 0.032** Germplasm/Landraces (24) 13.97 25.5 - 6.90 22 43.24 40.244 1.44E-13*** Introgressed lines(10) 14.74 19.1 - 9.72 8 16.94 15.239 0.00019*** Tropical Japonica (20) 23.60 32.43 - 13.03 18 65.62 6.2262 8.4E-05*** Released Varieties (30) 16.49 27.44 - 10.75 28 44.21 20.205 6.5E-11*** ** (P<0.01); *** (P<0.005)

Variation in photosynthesis in selected germplasm/land races

Variation in PN and gs in different groups of rice

Variation in photosynthesis rate in selected varieties of rice (Kharif-2012)

Variation in leaf photosynthetic traits among different wild rice species and cultivated varieties. Each value represents the mean of the respective species.

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