Research Journal of Agricultural Sciences 2, 3(1): 195-199 Assessment of Public and Private Rice with Special Reference to Seed Quality and Mycoflora P J Devaraju, K Vishwanath, K S Nagaraju and K P R Prasanna Department of Seed Science and Technology, University of Agricultural Sciences, Bangalore - 5 5, Karnataka, India e-mail: pjdseedtech@gmail.com A B S T R A C T Rice hybrids procured from private and public sectors were assessed for seed quality as well as field and storage fungi. Most of the hybrids performed well for seed quality attributes. 11 field and five storage fungi were detected by the blotter paper method. Among the seed mycoflora of rice hybrids namely, Pyricularia oryzae, Rhizopus, Alternaria Bipolaris oryzae, Curvularia sp. Dreschlera oryzae, Epiccum sp. Nigrospora sp. Phoma sp. Rhizoctonia oryzae, Trichinosis padwikii, Aspergillus sp. Cladosporim sp. Penicillium sp. and Fusarium were found to associated with seed externally as well as internally and acts as a source of infection. The prevalence of these fungi varied with respect to public and private sectors hybrids procured. In conclusion the hybrids on the whole recorded slight to highest percentage incidence of seed-borne mycoflora. The greater incidence in the level of seed-borne fungi resulted from seed production by different sources in varied agro-climatic conditions, thus differed for seed quality and frequency of mycoflora occurrence. Key words: Rice,, Seed-borne mycoflora, Seed quality Rice (Oryza sativa L.) is India s one of major staple food crop contributing 4% of total food grain production and is being cultivated over an area of 44.5 million hectare with a production of 4.7 metric tons. In Karnataka rice is grown over an area of 1.42 million hectare with an annual production of 3. metric tons (Anonymous 21). To sustain in coming decades, and to achieve self-sufficiency in rice, the production needs to be increased every year by almost 2 million tones. This is a daunting task; hence hybrid rice appears to be a feasible and readily adoptable option to increase the production and productivity of rice. Now 3,- 3,5 tons of hybrid rice seed is being produced annually in India out of which private sector accounts nearly about 95% (Anonymous 21). India alone requires.1 metric tons of hybrid rice by 25 (Barwale and Amarjit 1997). Several rice hybrids both from private and public sectors have been released for commercial cultivation. In addition to these about - hybrids developed by private sector are being marketed. Two private hybrids viz Pro-Agro-21 and PHB- 71 are popular. Among public bred hybrids and Sahyadri are becoming popular. It is estimated based on the seed produced and sold that hybrid rice is grown around.2 million hectares annually in various parts of India. The success of hybrid rice could be visualized only when there is adequate quality seed production and supply system. The hybrids are known to lose their viability more rapidly than high yielding varieties (Chen and Zhou 199). The split glumes nature of hybrid rice seed has a deleterious effect on the quality of seed lots as they manifest poor field emergence, seedling survival and serve as an easy avenue for the attack of pests and diseases (Zhou et al. 199). The crop is being affected with as many as 3 seed borne diseases (Noble et al. 195) of which 31 were caused by fungi. Many of these are known to be seed-borne and transmitted through seeds (Basak and Mridha 193). The prevalence of an individual seed-borne fungus varies depending on the location and hybrids. Although some work has been done on seed-borne fungi of rice with respect to location in the country, little attention has been paid to study the influence and association of fungi on the rice hybrid seeds. Therefore, the present study was undertaken to assess the seed quality and mycoflora of 24 rice hybrids procured from public and private sectors. MATERIALS AND METHODS Hybrid rice seeds were collected from public seed producer s viz. DRR Hyderabad, and V.C. Farm, Mandya and leading private seed producers viz Advanta, Hinduastan lever, Indo American Hybrid, J. K. Seeds, Mahyco, Nathseeds, Pioneer, Proagro, Prontline and Vikkys. The laboratory investigations were conducted at Department of Seed Science and Technology, University of Agricultural Sciences, GKVK, Bangalore, Karnataka, India. Seed quality parameters were evaluated by recording the following observations. Test weight (g), Standard germination (%) by between paper method as per ISTA (199), Seed length (mm), Seed width (mm), Seed thickness (mm 2 ) Electrical conductivity (µ mohs/cm), Nitrogen (%), Protein content (%) as given by Jockson (197). Detection of mycoflora was done by Blotter paper method as recommended by ISTA (199). Twenty five seeds in three replications of each hybrid were placed equidistantly in circles on three moist blotters dipped in.2% 2, 4-D solution to prevent germination of seeds in glass Petri dishes of 9cm diameter. Sufficient moisture was maintained by adding.2% 2, 4-D solution and the seeds were incubated at 25 ± 1 C with 195 www.rjas.info
Devaraju et al. hours light and hours dark alternate cycles. After seven days, the seeds were examined by a low power stereo binocular microscope and the different seed borne fungi found on the seeds were recorded. Discoloured and Infected Seeds (%) 2 24 2 1 4 PCA-32 PCA-1 URH-74 Fig 1 Discoloured (%), infected seeds (%) and germination (%) of rice hybrids Fig 2 Seedling vigour index-i and II of hybrids Nitrogen (%) Vigour Index-I 11 1 9 7 5 45 4 35 3 25 2 15 1 PCA-32 5 PCA-1 PCA-32 URH-74 PCA-1 URH-74 MRP-51 Fig 3 Nitrogen (%) and Protein (%) content of the hybrids RESULTS AND DISCUSSION Rice hybrids differed significantly for seed quality parameters (Table 1, 2). Among 24 hybrids evaluated recorded highest seed quality attributes viz Test weight (24.5g), germination (97%) root and shoot length of (14 and 15. cm), per cent nitrogen (.4) and protein (13.3) as illustrated in (Fig 3). While, lowest seed quality attributes were recorded in URH-74 with test weight (2.73g) and 3 per cent of germination. The significant increase in germination may be due to the increased test weight which might be positively related to germination. The seed length (9.mm), root (14.7cm), shoot length Indam 2-3 Discolored Seeds (%) Infected Seeds (%) Germination (%) MRP-51 SVI (I) MRP-51 Indam 2-3 Indam 2-3 SVI (I1) IR 525A Nitrogen (%) Protein content (%) IR 525A IR 525A IR 525 B IR 525 B IR 525 B IAH 22- IAH 22- IAH 22- IAH 2-4 IAH 2-4 IAH 2-4 IAH 2-4 IAH 2-4 IAH 2-4 IAH 2-11 IAH 2-11 IAH 2-11 4 2 1 9 7 5 1 Vigour Index-II 15 14 13 11 1 9 7 Germination (%) Protien (%) (17.33cm) and protein content (13.%) were significantly highest in IR-525B increased shoot length may be attributed to increased protein content of IR-5252 (Amaral and Dos 1979). Whereas, URH-74 recorded lowest seed length of.57mm, 13.4cm of root length and 17.73cm of shoot length. % Infection 3 2.5 2 1.5 1.5 PCA-32 PCA-1 URH-74 MRP-51 Indam 2-3 IR 525A IR 525 B IAH 22- IAH 2-4 IAH 2-4 IAH 2-11 Bipolaris oryzae Curvularia sp. Bipolaris oryzae Curvularia sp. Dreschlera oryzae Epiccum sp. Nigrospora sp. Phoma sp. Pypricularia oryzae Rhizoctonia oryzae Rhizopus sp. Sarocladium oryzae T. padwikii Fig 4 Field mycoflora associated with the hybrids used in the study The seed width differed significantly, among the hybrids tested, recorded highest seed width (3.13mm) which was on par with IAH 22- (3.mm), where as these two hybrids recorded average seed length as well as thickness and the lowest seed width was recorded in PCA-32 (2.47mm) and the seed thickness was highest in case of and (2.73mm 2 ) and the lowest was recorded in URH-74 (1.97mm 2 ) and Indam 2-3 (1.9mm 2 ). The results of the study on the EC of different hybrids revealed that the electrical conductivity (µ mhos/cm) differed significantly and the highest was observed in IAH 2-4 (39 µ mhos/cm) and the lowest EC was noticed in (4 µ mhos/cm) which was followed by IR-525A (154 µ mhos/cm). Indicating negative correlation between electrolyte leakage and seed quality these results are in line of Ghosh et al. (191). Whereas, the higher per cent discolored seeds were noticed in IAH 2-4 (23) which is followed by (1) how ever these two hybrids recorded 7 and 5% of total seed mycoflora, respectively. In contrast, Muhammad-Saifulla et al. (199) revealed that accumulation of toxic metabolites from the fungi resulted in increased seed discoloration. While, least number of discolored seeds were observed with MRP-51 (3) which recorded per cent total seed mycoflora, even though it recorded 9 per cent seed germination and less three per cent infected seeds. Highest germination (Fig 1) was recorded in (9%) followed by PCA-32,,, and PHP-71 (97%). Whereas, lowest was in (53.%). While, recorded highest number of total number of pathogens (14) even though germination per cent was recorded highest (97%). Similar findings were recorded by Zope and Thrimurthy (24) and concluded that in addition to varietal inheritance character of the seed, the seed borne infection might have also played a role in germination. However, lowest infected seeds were noticed in and KMP-3 (2) followed by proagro-444, MRP-51, Indam 2-3, and IAH 2-4 (3) where as highest Dreschlera oryzae Epiccum sp. Nigrospora sp. Phoma sp. Pypricularia oryzae Fungi Rhizoctonia oryzae Rhizopus sp. Sarocladium oryzae T. padwikii 19 www.rjas.info
Rice with Special Reference to Seed Quality and Mycoflora Table 1 Seed quality parameters of hybrids rice from different sources Test Seed Length Seed Width Seed Thickness EC (µ Discolored Germination Infected Weight (g) (mm) (mm) (mm 2 ) mohs/cm 2 ) Seeds (%) (%) Seeds (%) PCA-32 21.1 9.5 2.47 2.57 194 1 97 14 PCA-1 22.3 1.22 2.75 2.51 194 13 92 7 URH-74 2.73.57 2.51 1.97 27 4 3 1 21. 1.11 2. 2.5 53 15 21.22 1.37 2.7 2.73 1 94 21.53 1.5 2.71 2.53 27 7 93 7 22.75 9.95 2.1 2.5 25 1 94 4 22.4 9.7 2.75 2.73 214 13 93 3 21.1 9.13 2.51 2.52 241 93 5 23.73 9.13 2.7 2.51 25 1 3 5 MRP-51 23.95 9. 2.73 2.4 275 3 9 3 24.5 9.7 2.49 2.5 17 11 97 4 22.2 9.57 2.7 2.53 272 13 97 2 Indam 2-3 22.5 9.11 2.7 1.9 174 11 9 3 22.79 9.31 2.9 2.53 221 14 97 4 23.57 1.11 3.13 2.49 19 1 97 4 IR 525A 21.52 1.45 2.41 2.1 154 1 95 4 22.22.1 2. 2.47 4 94 2 IR 525 B 23.35.2 2.71 2.47 22 11 9 4 21.97 9.9 3.2 2.21 17 9 3 IAH 22-22.55.95 3. 2.3 2 1 1 5 IAH 2-4 21.2. 2.71 2.54 39 2 3 IAH 2-4 22.17 9. 2. 2.51 299 23 7 IAH 2-11 21.3.9 2.7 2.49 23 15 5 Mean 22.32 9. 2.744 2.451 223 11.3 9.5 5.75 CD @ 5 %.71..4 1.41 7.75 4.52 5.3 7.22 SEM ±.27.3.1.35 2.727 1.592 1.92 2.254 Table 2 Seedling characteristics, seed vigour index, nitrogen content (%) and protein (%) in rice hybrids Root length Shoot length Mean Seedling SDW Nitrogen Protein (Cm) (Cm) Length (Cm) (mg/1 Seedlings) SVI (I) SVI (I1) (%) content (%) PCA-32 15.9 19.5 35.4 114.5 344.47 7..71 PCA-1 1.3 1.4 35.3 119.5 325 7.7 7.. URH-74 13.1 17.73 3.3 114.3 2574 7.2 7.2 11.1.9 1.1 3.3.2 147 4.41 7.3.3 14.9 19.9 34.7 13. 3315.1.9 11.5 1.1 1.9 35. 145.1 3213.41 9. 11.4 17.4 23.1 4.3 93.7 317 1.3.2 13. 15.3 17. 33.23 5.2 3 7.43.4 13.1 1.33 17.5 33.9 115.1 31. 7. 11.73.73.53 24.93 19.4 23 4.9. 13.3 MRP-51 13.73 11.73 25.7 1.7 247 5.7.1 13.1 14. 15. 29. 142.2 247.2.4 13.3 15.1 1.5 33.33 135.1 2932 7.1 7.9.1 Indam 2-3 11.53 22.7 34.23 142.9 3297.72.4 13.73 1.13 17. 33.2 13.1 3231 9.41. 14.44 15.53 1.9 321 119.3 31.13.2 13.43 IR 525A 14.9 1.2 33.1 11.9 3172 7.99.4 13.5 14. 1.3 33.43 114. 314.2 7..53 IR 525 B 14.7 17.33 32.1 99.3 394 9.7.4 13. 15.93 17. 33. 9. 33 1..1 13. IAH 22-1.3 15.7 35.3 111.3 2 7.2 7. 11.57 IAH 2-4 1. 23.1 39.1 4.1 3237.1 7. 11.51 IAH 2-4 17.9 1.7 34. 99.7 2994.3 7..4 IAH 2-11 1.73 17.43 34.1 11.7 292 7. 7..73 Mean 15.22 17.93 15.7 2.5 31 7.57 7.954.1 CD @ 5 % 2.53 1.5 3. 11.2 4.7.9 1.149.735 SEM±.9.51 1.3 2.3 143.72.31.43.25 197 www.rjas.info
Devaraju et al. Table 3 Mycoflora associated with hybrid rice Hybrid A B C D E F G H I J K L M N O P Q R S T U V W X % seeds infected Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y Y B C D E F (1) Field Fungi Bipolaris oryzae 2 1 1 2 1 1 1 1 1 1 1 1 5 14.5 1-2 Curvularia sp. 1 1 1 1 1 5 21 5.21 <1 Dreschlera oryzae 1 1 2 1 1 1 1 1 1 1 1 1 5 13.54 1-2 Epiccum sp. 1 1 2 2. <1 Nigrospora sp. 1 1 1 1 1 1 5 25.25 <1 Phoma sp. 1 1 1 1 1 1 1 1 33.33 <1 Pyricularia oryzae 2 1 3 2 1 2 1 2 1 1 1 2 13 5 19.79 1-3 Rhizoctonia oryzae 1 1 1 1 3 17 4.17 <1 Rhizopus sp. 2 2 1 1 1 1 2 1 1 1 1 1 1 14 54 1.7 1-2 Sarocladium oryzae 1 1 2 2. <1 Trichinosis padwikii 1 1 1 1 1 1 5 25.25 <1 (A) Total 9 5 7 1 9 4 3 3 5 1 3 2 2 1 1 2 1 3 4 3 5 1-95 3.95 - (2) Storage fungi Alterneria Sp. 1 1 1 1 1 1 1 1 1 1 1 11 4 11.4 <1 Aspergillus sp. 2 1 2 1 1 1 1 1 1 2 1 2 1 13 54 17.71 1-2 Cladosporim sp. 1 1 1 1 4 17 4.17 <1 Fusarium sp. 1 1 1 1 1 1 1 1 1 2 1 1 1 13 54 14.5 1-2 Penicillium sp. 1 1 1 1 1 1 1 7 29 7.29 <1 (2) Total 5 4 5 3 4 2 1 2 1 3 1 1 4 4 2 1 1 3 1 1 4 4-53 2.21 - Total (1+2) 14 9 13 13 4 3 7 7 4 3 3 3 5 5 4 2 4 3 5 3 7 9 9 14.1 A: Percentage of seeds infected; Y: Percentage of seeds infected per sample; B: Total No. Of samples infected; C: % infection; D: Total number of seeds infected from all the samples; E: Mean % infection per sample; F: Range of infection Symbol Hybrid Symbol Hybrid Symbol Hybrid Symbol Hybrid A PCA-32 G M S IR 525 B B PCA-1 H N Indam 2-3 T C URH-74 I O U IAH 22- D J P V IAH 2-4 E K MRP-51 Q IR 525A W IAH 2-4 F L R X IA H 2-11 were noticed in (15). The hybrid recorded lowest field and storage fungi of 3 and 1%, respectively which might have resulted in significantly higher seedling length (4.3 cm) and vigour indices I and II (Fig 2) of 317 and 1.3, respectively. Similar findings were reported by Hiremath and Hegde (191). Increased number of seminal roots might have contributed for higher seedling length contributed towards higher seed vigour index. Verma and Singh (199), Deshpande (1993), Arian (1999) also found a positive relationship between seedling length and vigour index. Whereas, significantly lowest seedling length of 24.93cm in and vigour indices of 147 and 4.41, respectively in. Association of mycoflora on hybrid seeds Field fungi s among the 24 hybrids tested for association of seed Mycoflora, the percentage of seeds infected per sample was ranged from zero to three (Table 3, Fig 4). Similarly, total number of samples infected was highest with Rhizopus sp. (14%). The per cent infection was up to 54 with Rhizopus sp and the total number of seeds infected from all the samples (19) and mean per cent infection (1.79) was highest in Pyricularia oryzae. Similarly, in case of storage fungi, the percentage of seeds infected per sample was ranged from zero to two per cent. Total number of sample infected, per cent infection, total number of seeds infected form all the samples and the mean per cent infection (54) per sample Aspergillus sp. (17) and Fusarium sp. (14) were noticed highest among storage fungi recorded. The range of infection was highest being two per cent for Aspergillus sp. and Fusarium sp. Among the hybrids tested for field fungi per cent seeds infected per sample were lowest in MRP-51,, and (1%) and highest in (1%), and URH-74 (9%), and PCA-32 (7%), respectively. These differences might be due to abundant occurrence of fungal inoculums during crop growth period as well as warm and humid conditions during storage. and high yielding varieties on the whole has slight to highest percentage incidence of seed-borne mycoflora. The greater incidence in the level of seed-borne fungi might due to seed production at different localities from different sources which were produced in varied agroclimatic conditions, thus differed for seed quality and frequency of mycoflora occurrence. This might be due to pre and post-maturation environmental and physiological factors especially from flowering to seed development stage, increased moisture content experienced by the mother plant may be attributed for infection and invasion of pathogens as reported by Roberts and Ellis (19). The samples from localities with high relative humidity were severely infected, while those from the localities with low relative humidity 19 www.rjas.info
Rice with Special Reference to Seed Quality and Mycoflora show mild infection. Heydecker and Galleymore (1951), Duriaswamy and Mariappan (193), Singh (197), Indira and Rao (19) also found a positive correlation between amount of mycelium in the seed and level of relative humidity. LITERATURE CITED Amaral A and Dos P. 1979. Effect of weight and size of seeds on physiological quality and yield of rice grain. Lavoora Arrozseira 32(317): 24-2. Anonymous. 21. Hybrid rice in India: present status and future prospectus. Director of Rice Research, Hyderabad. Bulletin 3. Barwale and Amarjit S. 1997. Hybrid rice seed in India. Asian Seed 4(5): 15-17. Basak A B and Mridha O R. 193. Mycoflora associated with different varieties of rice seeds collected from Chittagong district. Chittagong Uni Studies 7: 119-3. Chen L B and Zhou G Q. 199. Correlation between permeability of membranes and germination of rice seeds. Plant Physiology and Communication 73: 31-34. Deshpande V K. 1993. Effect of provenance method of propagation and techniques of seed production on seed yield and quality of hybrid rice (Oryza sativa L.). Ph. D. Thesis, UAS, Bangalore, Karnataka, India. Duriaswamy S S and Mariappan V. 193. Rice colour discolouration. International Rice Research News : 9-1. Ghosh B, Adhikary J and Banerjee N C. 191. Changes of some metabolites in rice seeds during ageing. Seed Science and Technology 9: 49-473. Heydecker W and Galleymore. 199. The vigour of seeds: a review. Proceedings of International Seed Test Association 34: 21-219. Hiremath P C and Hegde R K. 191. Role of seed-borne infection of Drechslera oryzae on the seedling vigour of rice. Seed Research 9(1): 45-4. Indira K and Rao J G. 19. Storage fungi in rice in India. Kavaka 14: -7. ISTA. 199.Rules for seed health testing. Proceedings of International Seed Test Association 31: 17-114. Jockson M L. 197. Soil Chemical Analysis. Pretiee Hall of India (Pvt). New Delhi. pp7-214. Muhammad-Saifulla H S, Shetty M and Krishnappa M. 199. Effect of seed treatment on discoloured rice grains. Indian Journal Mycology and Plant Pathology 2(1): 7-9. Noble M, Thmpe J D and Paul N. 195. An annotated list of seed-borne diseases. Commonwealth Mycol. Inst. Kew, Survey, England. pp159-1. Roberts E H and Ellis R H. 19. Seed physiology and seed quality in soybean. Advances in Legume Science 297-331. Singh N I. 197. Pestalotia oryzae a new rice fungi. International Rice Research News : 32. Verma O P and Singh P V. 199. Path analysis of seedling characters in rice. Narendradeva Journal of Agricultural Research 4(1): -14. Zhou Z Y and Tang S D, Hu J Y M. 199. Effect of infection and imperfect closed glume on germination of hybrid rice seed. International Rice Research News 14(5): 4. Zope A V and Thrimurthy V S. 24. Seed health evaluation in rice varieties and seed germination. Journal of Mycology and Plant Pathology 34: 525-527. 199 www.rjas.info