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Photosynthate remobilization to grain in common bean contributes to
               improved resistance to terminal drought...
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Poster23: Photosynthate remobilizationto grain in common bean contributes to improved resistance to terminal drought stress


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Poster23: Photosynthate remobilizationto grain in common bean contributes to improved resistance to terminal drought stress

  1. 1. Photosynthate remobilization to grain in common bean contributes to improved resistance to terminal drought stress Jose A. Polanía, M. Rivera, M. Grajales, C. Cajiao, S. Beebe and I. M. Rao International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia E-mail:; Introduction Under rainfed conditions, significant genotypic differences were observed in canopy biomass production at mid-pod The elite lines SER 128, SER 78, SEA 15, NCB 226, SEN 56, SEN 36, SER 119 and SER 113 yielded well under Drought is the major abiotic constraint affecting common filling growth stage (Figure 2). Higher values of canopy rainfed conditions due to greater ability to partition biomass could indicate greater potential for remobilization photosynthetically assimilated carbon to pods as reflected bean (Phaseolus vulgaris L.) production. About 60% of the of photosynthates to grain during drought stress. Cowpea bean crop is cultivated under the risk of either intermittent cv. Mouride showed markedly greater value of canopy by higher values of pod partitioning index (Figure 3). The or terminal drought (Beebe at al., 2008; Rao, 2001; biomass than the common bean genotypes. Among the line SER 118 was outstanding in remobilization of White and Singh, 1991). The effects of drought on genotypes of P. vulgaris tested, NCB 226, SXB 418, DOR photosynthates under terminal drought stress as indicated common bean are dependent on the intensity, type and 390, SER 78 and SER 113 were outstanding in canopy by greater values of both pod partitioning index and pod duration of the stress. Improving drought resistance of biomass production. harvest index but it had lower value of canopy biomass common bean varieties is an important research for (Figure 2, 3 and 4) indicating the need for adequate development strategy to minimize crop failure and 1600 vegetative vigor to achieve higher values of grain yield. In improve food security in bean growing regions. Field contrast to SER 118, cowpea cv. Mouride showed lower Rainfed grain yield (kg ha-1) 1400 SER 78 studies conducted for the past few years indicated that the SER 128 NCB 280 NCB 226 value of pod partitioning index indicating a limitation on superior performance of common bean genotypes under 1200 SEA 15 SER 119 SEN 36 G 40001 SEN 56 Cowpea M remobilization of photosynthates to pod development. both terminal and intermittent drought stress was 1000 EAP 9653-16B SEA 5 SER 118 SER 113 SER 16 associated with their ability to remobilize photosynthates Mean: 898 A 774 Results on the relationship between rainfed pod harvest 800 SXB 405 from vegetative structures to developing grain. Among the LSD0.05: 319 Tio Canela BAT 477 DOR 390 index (PHI) and rainfed grain yield indicated that two plant traits evaluated using a large number of both elite 600 Perola San Cristobal SXB 418 small seeded red lines (SER 78, SER 128) and four small lines and recombinant inbred lines, pod harvest index was 400 A 686 seeded black lines (NCB 226, NCB 280. SEN 36 and SEN identified as a useful trait to consider in the breeding 56) were superior in mobilizing photosynthates from pod 200 program in addition to grain yield for identifying bean G 19902 wall to seeds (Figure 4). The PHI values of the two wild genotypes that are better adapted to both terminal and 0 G 24390 Mean: 2781 LSD0.05: 981 bean accessions (G 19902 and G 24390) were markedly intermittent drought stress conditions. We evaluated lower than that of other bean genotypes. Results on drought adaptation of 36 genotypes including the elite 500 1000 1500 2000 2500 3000 3500 4000 4500 agronomic water efficiency indicated that the elite lines lines and checks from the on-going breeding program with Rainfed canopy biomass (kg ha-1) SER 78, NCB 226 and SER 128 were highly efficient in the the main objective of defining the physiological basis for Figure 2. The relationship between rainfed grain yield and use of water applied under rainfed conditions (Figure 5). improved drought resistance. rainfed canopy biomass. Correlation coefficients between grain yield and other Materials and Methods 1600 shoot attributes indicated that seed yield was positively related to canopy biomass, pod partitioning index and Rainfed grain yield (kg ha-1) 1400 SER 78 SER 128 A field trial was conducted at CIAT-Palmira in 2009 (July 1200 NCB 280 NCB 226 SEN 36 SEA 15 pod harvest index under rainfed conditions (Table 1). G 40001 to October) to determine genotypic differences in Cowpea M SEN 56 SER 119 tolerance to drought stress conditions. The trial included 36 1000 SXB 415 SER 16 SER 113 SER 109 Table 1. Correlation coefficients (r) between grain yield and other shoot attributes under irrigated and rainfed SEA 5 SER 118 genotypes: A 686, A 774, BAT 477, Carioca, Cowpea 800 Mean: 898 SXB 405 RCB 273 A 774 Mouride, DOR 390, EAP 9503-32B, EAP 9653-16B-1, G LSD0.05: 319 SXB 418 Tio Canela Carioca conditions. *, **, *** Significant at the 0.05, 0.01 and 0.001 probability levels, respectively. DOR 390 BAT 477 19902, G 24390, G 40001, NCB 226, NCB 280, Perola, 600 Perola RCB 273, San Cristóbal 83, SEA 15, SEA 5, SEN 36, SEN 400 San Cristobal A 686 Plant traits Irrigated Rainfed 56, SER 109, SER 113, SER 118, SER 119, SER 125, SER 128, SER 16, SER 48, SER 78, SER 90, SXB 405, SXB 409, 200 Canopy biomass (kg ha-1) -0.01 0.59*** SXB 412, SXB 415, SXB 418 and Tio Canela 75. A 6 x 6 0 G 19902 Pod partitioning index (%) 0.49** 0.79*** G 24390 partially balanced lattice design with 3 replicates was Mean: 63 Pod harvest index (%) 0.64*** 0.61*** used. Two levels of water supply (irrigated and rainfed) 0 20 40 60 80 100 were applied. Experimental units consisted of 4 rows of 3.72 m long by 0.6 m wide. Canopy dry weight per area was measured at mid-pod filling under rainfed and Rainfed pod partitioning index (%) Figure 3. The relationship between rainfed grain yield and Conclusions irrigated conditions in order to determine genotypic Field evaluation of elite lines at Palmira under terminal rainfed pod partitioning index. variation in drought resistance. At the time of harvest, drought stress resulted in identification of six small seeded grain yield and yield components were determined. Pod 1600 common bean lines (NCB 226, NCB 280, SEN 56, SER 113, partitioning index (dry wt of pods at harvest/dry wt of SER 78 and SER 128) that were outstanding in their Rainfed grain yield (kg ha-1) 1400 SER 78 canopy biomass at mid-podfill x 100), pod harvest index 1200 SER 128 NCB 226 SEA 15 NCB 280 adaptation to terminal drought stress conditions. The (dry wt of seed at harvest/dry wt of pod at harvest x SEN 36 G 40001 SEN 56 superior performance of these lines under drought stress 100), were also determined (Figure 1). 1000 SXB 415 SEA 5 SER 16 Cowpea M SER 109 was associated with higher values of canopy biomass, pod A 774 SER 118 800 Mean: 898 LSD0.05: 319 SXB 405 Carioca RCB 273 Tio Canela partitioning index and pod harvest index reflecting the BAT 477 600 SXB 418 DOR 390 Perola contribution of remobilization of photosynthates to grain. San Cristobal A 686 Further work is in progress to evaluate these lines for their 400 deep rooting ability under drought stress conditions. 200 0 G 19902 G 24390 Mean: 72 LSD0.05: 8 References 30 40 50 60 70 80 90 Beebe, S., I. M. Rao, C. Cajiao and M. Grajales. 2008. Rainfed pod harvest index (%) Selection for drought resistance in common bean also Figure 4. The relationship between rainfed grain yield and improves yield in phosphorus limited and favorable environments. Crop Science 48: 582-592. 1 rainfed pod harvest index. Rao, I. M. 2001. Role of physiology in improving crop 2 14 adaptation to abiotic stresses in the tropics: The case of Irrig a te d common bean and tropical forages. In: M. Pessarakli (ed). Agronomic water efficiency 12 R a in fe d Figure 1. Photosynthate remobilization pathway. 1 Handbook of Plant and Crop Physiology. Marcel Dekker, (kg ha-1 mm-1) Mobilization of photosynthates from leaves and stems to 10 Inc., New York, USA pp. 583-613. pods (pod partitioning index). 2 Mobilization of 8 White, J. W., and S. P. Singh. 1991. Breeding for photosynthates from pod wall to seed (pod harvest index) adaptation to drought. p. 501-506. In A. van Schoonhoven Results and Discussion 6 and O. Voyset (ed.) Common beans: Research fro crop 4 improvement. CAB International. Wallingford, UK & CIAT, 2 Cali, Colombia. During the crop-growing season, maximum and minimum air temperatures were 32.6 oC and 19.4 oC. The total rainfall during the active crop growth was 59 mm. The 0 Acknowledgements 75 6 8 0 5 2 0 78 15 36 56 el 5 22 12 28 12 90 39 an A a potential pan evaporation was of 482 mm. These data on A R N N E 19 24 B B R R E E E E S C E C E S S S S G G This work is partially supported from the funds from BMZ- S S N N total rainfall and pan evaporation together with decrease C o Ti in soil moisture across soil depth (-24 KPa in irrigated vs. - G e n o typ e s GTZ), Generation Challenge Program of CGIAR (Tropical 108 KPa ia rainfed at 60 days after planting at 40-60 cm Figure 5. Agronomic water efficiency (grain yield (kg/ Legumes I Project) and Bill and Melinda Gates Foundation soil depth) indicated that the crop suffered severe terminal ha)/unit water applied (mm) of 12 genotypes grown under (Tropical Legumes I and II projects). drought stress during active growth and development. irrigated and rainfed conditions.