106 Rice Science, 2004, 11(3): 106–112 http://www.ricescience.info Analysis on Mineral Element Contents in Associated with Varietal Type in Core Collection of Yunnan Rice 1 2 2 1 3 3 ZENG Ya-wen , LIU Jia-fu , WANG Lu-xiang , SHEN Shi-quan , LI Zi-chao ，WANG Xiangkun , 1 1 WEN Guo-song , YANG Zhong-yi (1Crop Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming 650205, China; E-mail: [email protected]; 2Analysis and Testing Center, Yunnan Academy of Agricultural Sciences, Kunming 650223, China; 3College of Crop Science, China Agricultural University, Beijing 100094, China) Abstract: Eight-element contents of 653 unpolished rice samples harvested from Xingping experiment farm, Yunnan Province under the same ecological conditions were analyzed by ICP-AES method. The mineral elements content were closely related to low diversity, high-yielding, and multi-resistance breeding; The K, Mg, Ca and Mn content in high-yielding and resistant varieties were high, and other nutrients such as P, Fe, Zn and Cu were low, which was connected with the heredity and physiological mechanism of mineral nutrients. There is zonal distribution of mineral elements content from Yunnan rice, especially for P, Fe, Zn and Cu co-related with the diversity center, paddy versus upland, glutinous and non-glutinous, glume-hair versus nuda, rice color, rice flavor, soft rice versus non-soft rice, but it did not find any association with indica-japonica types. The results supported the ecological variety group view of 5-grade taxonomic system “species-subspecies-ecological groups-ecological variety groups–varietal types”. Key words: Yunnan rice; core collection; mineral elements; varietal type Rice improvement in grain mineral elements content rice genetic and ecological diversity in China, and 13 is always one of the major targets for rice breeders. An counties where constituted the genetic diversity center of investigation conducted by FAO showed that the Yunnan rice landraces [8, 9]. On the basis of Cheng element contents such as Fe, Zn, Mn, etc. in the foods of Kansheng and Wang Xiangkun’s taxonomic studies most developing countries decreased obviously in conducted on Asian cultivated rice, Yu Luqi’s divided 1979-1995. For example, in Asia, about 40% of sterile 6 121 accessions of Yunnan rice landraces into 2 women and 50% of pregnant women suffered from subspecies, 6 ecological groups and 58 ecological iron-deficiency anemia, and there were more than 1 500 variety groups. In Yunnan, the number of ecological millions children being short of Zn. For this reason, varieties is almost the total of those found in China, and seeking the crop germplasm resources and breeding new the cultivars account for 8.6% of the whole cultivars in crop varieties with high mineral elements content China. The characteristics of these varieties and their became the key aim to resolve this risk of nutrition. As English names had been reported systematically [10]. In mineral elements play a very important role in any this paper, contents of eight mineral elements for the biological organism, they are not only important in the core collection of Yunnan rice were measured, the composition of botanical genes-enzyme (e.g. P, Fe, Zn, relationship of mineral elements content with variety Cu and Mn), but also the key factors for the types was analyzed, which should provide a basic physiological and biochemical reactions of plant (e.g. K, reference for rice quality breeding, rice variety Ca, Mg) [1-3]. Some studies on genetic analysis for the classification and the industrial development of special contents of several mineral elements in rice were widely purpose rice. undertaken in China and abroad, as well as the relationship with rice color, original location and the MATERIALS AND METHODS K-efficient genotype [4-7], but there was no report to date about the variation in element content between different Location and site characteristics type rice such as indica and japonica, paddy and upland, glutinous and non-glutinous, grain color, awn or awnless, Experimental plots were located at Bamencun hard and soft-, fragrant-rice under the same ecological village of Yaojie town, Xinping County, Yunnan conditions. Yunnan is thought to be the main center of Province, regarded as double-cropping rice zone with an elevation of 500 m and a very hot climate. Because of Received: 24 October 2003; Accepted: 12 January 2004 strong desilicification and Al enrichment during soil forming, the red mudstone paddy soil is slightly acidic ZENG Ya-wen, et al. Analysis on Mineral Element Contents in Associated with Varietal Type in Core Collection of Yunnan Rice 107 with rich contents of Fe and Al, the organic matter 1.8%, solution was properly diluted and analyzed with N 0.06%, P 0.03%, K 1.8% in topsoil. The previous crop ICP-AES meter. of the experimental plots was watermelon. Six hundred and fifty-three accessions of core collection from RESULTS Yunnan rice were sowed on 28 April, transplanted on 20 May and harvested in October 1999, without any Analysis of phosphorus (P) and potassium (K) fertilizer application during the whole growth period. contents High temperature and rich rainfall constituted the characteristics of weather from tillering to heading stage, The average value of P content in core collection of the highest water temperature of 41℃ in the fields was Yunnan rice reached to 3 812.56 mg/kg, including rice recorded during early tillering stage. Even during grain landraces with a value of 460.34 mg/kg being higher filling and ripening stages, rainfall was relatively higher than that of improved cultivars. The highest value was yet. Besides the two times of irrigations applied during recorded in Laolaihong from Yongde County and the tillering phase, the rich rainfall provided enough water to lowest one was Xiaohuangguanuo from Puer County for rice during all of the other growth periods. rice landraces; the maximum value was noticed in Dianrui 449 and the lowest one was Dianyu 1 for Determination of element content improved cultivars (Table 1). There were 72 accessions The contents of 8 mineral elements, i.e. P, K, Ca, landraces whose P contents were higher than that of the Mg, Fe, Zn, Cu and Mn in rice seeds were tested at highest one in improved cultivars, and these 72 Analysis and Testing Center, Yunnan Academy of accessions landraces were widely distributed in 28 Agricultural Sciences. Unpolished rice (0.5 g) of each counties such as Yongde (15), Menghai (13), etc., which sample was put into a beaker, followed by adding 5 mL mainly constitute the genetic diversity center of Yunnan of nitric acid and 1 mL of perchloric acid. The beaker rice landraces. Most of the rice landraces with a P was heated electrically in sand bath to nitrify and content higher than 5 000 mg/kg belonged to Yongde (6) decompose rice till the solution became clear. The and Menghai counties. Therefore, rice diversity center clear solution was continuously heated and evaporated to was probably also the rich area for rice effective P gene just dry, the residue was dissolved with 5 mL of 1:1 resources. The variation in P content for core collection hydrochloric acid and the solution was transferred into a of Yunnan rice was not associated with the difference in 50-mL volumetric flask to test. Finally, the resultant characters such as indica-japonica, paddy-upland, Table 1. Phosphorus and potassium contents in core collection of Yunnan rice. mg/kg No. of Phosphorus (P) Potassium (K) Rice type accessions Mean SD Minimum Maximum Mean SD Minimum Maximum Core collection 653 3812.56 500.36 2162 5370 2673.22 395.51 1719 4528 Improved cultivar 70 3401.57 350.53 2634 4422 3368.83 369.34 2769 4628 Landraces 583 3861.91 493.10 2162 5370 2589.7 306.4 1719 3634 indica 274 3856.08 476.78 2559 5282 2592.62 286.72 1981 3580 japonica 307 3865.56 508.35 2162 5370 2588.27 318.96 1719 3634 Paddy 405 3904.42 496.09 2162 5370 2598.14 294.82 1909 3580 Upland 177 3865.94 474.73 2634 5354 2571.07 332.18 1719 3634 Glutinous 465 3865.41 490.65 2634 5370 2559.54 300.38 1719 3580 Non-glutinous 118 3848.1 504.54 2162 4899 2708.56 288.39 1909 3634 White 332 3883.28 460.47 2162 5370 2630.51 291.96 1909 3634 Red 233 3826.14 523.79 2559 5290 2516.26 304.61 1719 3485 Purple 18 3930.72 619.77 2634 4899 2787.56 374.58 1981 3492 Glume hair 504 3888.98 499.59 2162 5370 2596.79 304.14 1719 3634 Nuda 79 3689.20 412.05 2902 5044 2544.44 318.76 2049 3189 Awn 40 4078.20 508.41 3081 5290 2590.94 307.64 1179 3634 Awnless 543 3847.81 488.14 2162 5370 2572.88 292.27 1996 3264 Common rice 565 3862.67 496.47 2162 5370 2588.49 308.71 1719 3634 Fragrant rice 18 3837.94 382.19 3127 4498 2627.44 225.84 2146 3150 Soft rice 12 4179.41 557.23 3505 5282 2516.67 337.01 2174 3033 108 Rice Science, Vol. 11, No. 3, 2004 Table 2. Calcium and magnesium content in core collection of Yunnan rice. mg/kg No. of Calcium (Ca) Magnesium (Mg) Rice type accessions Mean SD Minimum Maximum Mean SD Minimum Maximum Core collection 653 263.72 510.23 57.9 3107.0 1549.08 225.60 14.6 2564.0 Improved cultivar 70 1274.52 1120.88 57.9 3107.0 1822.99 246.48 1307.0 2564.0 Landraces 583 142.35 70.71 61.6 917.0 1516.19 199.27 14.6 2021.0 indica 274 142.62 50.88 61.8 688.0 1500.35 171.45 14.6 1966.0 japonica 307 142.07 84.84 64.0 917.0 1530.10 221.05 15.8 2021.0 Paddy 405 142.07 66.27 61.8 917.0 1532.67 200.20 15.8 2021.0 Upland 177 141.17 80.25 64.0 711.0 1479.01 192.98 14.6 1910.0 Glutinous 465 145.22 76.98 61.8 917.0 1472.85 198.66 14.6 1910.0 Non-glutinous 118 131.06 34.70