INTRODUCTION Potato (Solanum tuberosum L.) is one of the most important food crops both in the developing and the developed countries. Potato processing is well advanced in developed countries, but now processing industry in the developing countries is also growing fast. In India, there is an increase in processing activity due to an increase in urban population, preference of the new generation for fast foods, rise in per capita income, and increase in the number of working women (preferring ready-to-cook foods) and an expanding tourism (Marwaha, 1997). Processing of potatoes solves the problem of storing large quantities of this commodity during periods of glut. A large number of companies, including multinationals, have stepped into the field of potato processing. The processing industry needs potatoes with high dry matter (over 20%), low amounts of reducing sugars (below 0.25% on fresh weight basis), and low amounts of phenols (Gaur et al, 1999). In the state of Punjab, the main-season crop is grown under short-day conditions beginning in October, and is Evaluation of potato genotypes for processing traits in late autumn Prabhjot Kaur, V.K. Vashist and Ajay Kumar1 Department of Vegetable Science Punjab Agricultural University, Ludhiana - 141 001, India 1E-mail: ajaykpau@gmail.com ABSTRACT The present study was undertaken to evaluate potato genotypes for their suitability for processing when grown under different crop durations, i.e., E1 (80 days’ crop duration), E2 (100 days’ crop duration) and E3 (120 days’ crop duration). Among the three durations studied, E3 yielded the highest processing-grade yield (q/ha), followed by E2 and E1. The crop in E3 also exhibited high dry-matter content and low levels of reducing sugars compared to that in the other crop durations, which is desirable for processing. Among the cultivars under study, Kufri Badshah, Kufri Anand, Kufri Bahar, Kufri Chipsona-1, Kufri Chipsona-2, Kufri Ashoka and Kufri Jawahar gave the highest total tuber-yield. However, for processing-grade yield, cvs. Kufri Badshah, Kufri Chipsona-1 and Kufri Jawahar yielded significantly better than the mean, but cv. Kufri Chipsona-1 was the one found suitable for processing due to its high dry-matter content (22.07%), while, the other cultivars were found suitable for table purpose alone. Though cv. Kufri Chipsona-1 yielded higher (309.39 q/ha), its performance could not be predicted under various conditions owing to the data on regression coefficient (being less than one), and a significant deviation from regression. Cultivars Kufri Chipsona-1 and Kufri Chipsona-2 were found to be suitable for processing, with high tuber- and processing-grade yield, high dry-matter content, low amount of reducing sugars and phenols in the crop durations E2 and E3. Both these cultivars produced chips of acceptable colour in all three crop durations. Key words: Potato, genotypes, autumn season, processing quality J. Hortl. Sci. Vol. 10(1):57-63, 2015 harvested in January/ February. During crop maturation, the average minimum temperature is 4.5°C, which results in relatively low dry-matter content and high levels of reducing sugars (Ezekiel et al, 1999). Days to harvest also affect processing quality in potato, viz., its dry matter content, sugar content, reducing sugars, phenolic compounds, and specific gravity (Marwaha and Sandhu, 2002). Therefore, identifying suitable varieties for late-autumn planting in the North- Western plains will not only ensure supply of fresh potatoes to the processing industry of North India for a longer period, but also minimize transportation charges, and save on the storage cost of tubers (Pandey et al, 2003). MATERIAL AND METHODS The experimental material comprised ten genetically diverse potato genotypes, viz., Kufri Badshah, Kufri Anand, Kufri Chandramukhi, Kufri Bahar, Kufri Lauvkar, Kufri Chipsona-1, Kufri Chipsona-2, Kufri Ashoka, Kufri Jawahar and Russet Nor x 97-ES-33, obtained from Central Potato Research Institute (CPRI), Shimla. These were multiplied at Vegetable Research Farm of Department of Vegetable 1Farm Advisory Service Scheme, Amritsar-143001, Punjab, India 58 Science, PAU, Ludhiana. All the ten cultivars were evaluated in Randomized Block Design (RBD), with three replications. Each plot measured 3.2m x 1.2m, and consisted of 16 plants in each row. Seed-sized tubers were planted at row-to-row and plant-to-plant spacing of 60cm and 20cm, respectively. The crop was planted on 16th November 2005. Three experiments were laid out for different crop durations, viz., 80, 100 and 120 days. Various crop durations are symbolized below: Environment-I (E1) – Haulm cutting 80 days after planting Environment-II (E2)– Haulm cutting 100 days after planting Environment-III (E3)– Haulm cutting 120 days after planting Each crop was harvested at 10-15 days at haulm cutting. The crop was raised following a package of practices for potato recommended by Punjab Agricultural University, Ludhiana. Processing characters like dry-matter content (%), total amount of sugars (Yemm and Willis, 1954), reducing sugars (mg/100g fresh weight) (Nelson, 1944), total amount of phenols (Swain and Hillis, 1959) and polyphenol oxidase chip colour (score), were all studied. Statistical analysis of variance was carried out for Randomized Block Design for each character separately, in each of the three environments (crop duration cycles). Phenotypic stability analysis of genotypes was assessed for their stability of performance over environments, using a model suggested by Eberhart and Russell (1966). The following model was used for describing performance of a variety over a series of environments: Yij = μi + βiIj + δij where, Yij = Variety Mean of the i th variety at the jth environment (where i=1, 2 …….g, j=1, 2 ……….n) μi = Overall Mean of the ith genotype over all the environments βi = Regression coefficient of i th variety to the varying environments Ij = Environmental index obtained as the Mean of all genotypes at the jth environment minus the Grand Mean, i.e., Ij = where, Σj Ij = 0 δij = Deviation from regression of the i th variety in jth environment g = Number of genotypes n = Number of environments Stability parameters of individual genotypes were calculated as per Eberhart and Russell (1966). RESULTS AND DISCUSSION Cultivars Kufri Chipsona-1 (161.47 q/ha), Kufri Chipsona-2 (209.23 q/ha) and Kufri Ashoka (151.03 q/ha) had significantly higher processing-grade yield than the Mean value (124.49 q/ha) in E1. However, in the case of E2, cvs. Kufri Badshah (200.70 q/a), Kufri Bahar (169.30 q/ ha), Kufri Lauvkar (180.57 q/ha), Kufri Chipsona-1 (174.50 q/ha) and Kufri Chipsona-2 (189.57 q/ha) yielded significantly higher than the Mean (152.85 q/ha). In the third environment (E3), cvs. Kufri Badshah (325.03 q/ha), Kufri Chipsona-1 (224.50 q/ha) and Kufri Jawahar (224.87 q/ha) gave significantly better yield than the Mean value (196.16 q/ha) (Table 1). Analysis of pooled data revealed that cvs Kufri Badshah and Kufri Chipsona-2 had significantly higher processing-grade yield (215.47 q/ha and 196.02 q/ha, respectively) than the pooled Mean (157.83 q/ha). In the case of environment E1, cvs. Kufri Chipsona- 1 and Kufri Chipsona-2 showed significantly higher dry- matter content than the Mean value. However, in the case of E2, cvs. Kufri Anand, Kufri Chipsona-1, Kufri Chipsona- 2 and Russet Nor x 97-ES-33 showed significantly higher dry-matter content than the Mean. In E3, cv. Kufri Chipsona- 1 alone had significantly higher dry-matter content than the Mean value. Pooled data analysis indicated that cvs. Kufri Anand, Kufri Chipsona-1, Kufri Chipsona-2 and Russet Nor x 97-ES-33 had significantly higher Mean value than the pooled Mean. Kufri Chipsona-1 had the highest dry-matter (20.69%), followed by Kufri Chipsona-2 (19.93%), Russet Nor x 97-ES-33 (19.83%) and Kufri Anand (19.74%) (Table 2). Cultivars Kufri Chipsona-1, Kufri Chipsona-2 and Russet Nor x 97-ES-33 had a high Mean dry-matter content, with regression coefficient less than one (0.74, 0.22 and 0.90, respectively) and a non-significant deviation from regression, showing their suitability for cultivation under diverse environmental conditions. Studies of Patel et al (2003) and Pandey et al (2005) also support the above findings. In environments E1 and E2, cvs. Kufri Chandramukhi, Kufri Lauvkar, Kufri Chipsona-1, Kufri Chipsona-2 and J. Hortl. Sci. Vol. 10(1):57-63, 2015 Prabhjot Kaur et al 59 Table 2. Mean , regression coefficient (bi) and deviation from regression (S2di) for dry matter content (%) in potato during the autumn season 2005-2006 Sl. Genotype E1 E2 E3 Overall bi S 2di No. Mean 1. Kufri Badshah 15.21 17.49 18.96 17.22 1.04 0.03 2. Kufri Anand 18.58 20.29 20.36 19.74 1.04 0.09 3. Kufri Chandramukhi 16.04 18.54 21.27 18.62 1.44 0.10 4. Kufri Bahar 16.25 19.04 18.98 18.09 0.78 1.08* 5. Kufri Lauvkar 16.81 17.02 18.72 1752 0.51 0.47 6. Kufri Chipsona-1 19.37 20.63 22.07 20.69 0.74 0.04 7. Kufri Chipsona-2 19.17 20.74 19.87 19.93 0.22 0.93 8. Kufri Ashoka 14.44 17.10 21.29 17.61 1.87 0.85 9. Kufri Jawahar 14.53 17.44 19.87 17.28 1.47 0.00 10. Russet Nor x 97-ES-33 18.04 20.19 21.26 19.83 0.90 0.09 Mean 16.84 18.85 20.26 18.65 CD (5%) 1.86 1.32 1.10 0.90 SE of bi = 0.24 CV 5.78 4.14 3.41 *Significant at 5% Table 3. Mean , regression coefficient (bi) and deviation from regression (S2di) for total amount of sugars (mg/100g fresh weight) in potato during the autumn season 2005-2006 Sl. Genotype E1 E2 E3 Overall bi S 2di No. Mean 1. Kufri Badshah 975.67 816.33 571.67 787.89 1.59 9435.81* 2. Kufri Anand 692.67 477.00 369.33 513.00 1.37 56.93 3. Kufri Chandramukhi 494.67 371.33 326.00 397.33 0.72 21.95 4. Kufri Bahar 736.67 467.00 356.67 520.11 1.62 16.19 5. Kufri Lauvkar 487.67 334.00 293.00 371.56 0.85 208.03* 6. Kufri Chipsona-1 347.67 288.67 268.67 301.67 0.34 10.07 7. Kufri Chipsona-2 304.67 270.00 232.33 269.00 0.29 156.36* 8. Kufri Ashoka 748.33 483.33 432.00 554.56 1.39 1268.33* 9. Kufri Jawahar 668.33 405.67 375.67 483.22 1.31 2197.54* 10. Russet Nor x 97-ES-33 511.00 416.67 390.67 439.44 0.52 70.49 Mean 596.73 433.00 361.60 463.78 CD (5%) 16.57 12.10 12.39 54.43 SE of bi = 25.92 CV 2.08 1.52 1.56 *Significant at 1% Table 1. Mean , regression coefficient (bi) and deviation from regression (S2di) for processing-grade yield (q/ha) in potato during the autumn season 2005-2006 Sl. Genotype E1 E2 E3 Overall bi S 2di No. Mean 1. Kufri Badshah 120.67 200.70 325.03 215.47 2.85 0.55 2. Kufri Anand 90.30 147.47 212.70 150.16 1.69 50.02 3. Kufri Chandramukhi 93.78 48.57 87.68 76.67 0.00 1203.67* 4. Kufri Bahar 133.68 169.30 197.93 166.97 0.88 68.23 5. Kufri Lauvkar 105.03 180.57 140.60 142.07 0.38 2482.04* 6. Kufri Chipsona-1 161.47 174.50 224.50 186.82 0.90 93.30 7. Kufri Chipsona-2 209.23 189.57 189.26 196.02 -0.26 90.91 8. Kufri Ashoka 151.03 153.63 219.30 174.66 1.00 391.86* 9. Kufri Jawahar 69.45 164.07 224.87 152.80 2.11 720.22* 10. Russet Nor x 97-ES-33 110.27 100.20 139.73 116.73 0.45 310.28* Mean 124.49 152.85 196.16 157.83 CD (5%) 16.11 14.64 23.73 34.52 SE of bi = 0.45 CV 5.95 5.40 8.76 *Significant at 1% J. Hortl. Sci. Vol. 10(1):57-63, 2015 Evaluation of potato genotypes for processing traits in late autumn 60 Russet Nor x 97-ES-33, had significantly less amount of total sugars than the Mean. Cultivars Kufri Anand, Kufri Chandramukhi, Kufri Lauvkar, Kufri Chipsona-1 and Kufri Chipsona-2 had significantly lower amount of total sugars than the Mean in E3 (Table 3). In pooled analysis of data, four cultivars, viz., Kufri Chandramukhi, Kufri Lauvkar, Kufri Chipsona-1 and Kufri Chipsona-2, had significantly lower Mean of total level of sugars than did the pooled Mean. ‘Kufri Chipsona-2’ had the lowest mean of total level of sugars (269.00mg), followed by Kufri Chipsona-1 (301.67mg), Kufri Lauvkar (371.56mg) and Kufri Chandramukhi (397.33mg) per 100g on fresh-weight basis. Cultivars Kufri Chandramukhi, Kufri Chipsona-1, Kufri Chipsona-2 and Russet Nor x 97-ES-33 had lower Mean values for total amount of sugars as less than one regression coefficient (0.72, 0.34, 0.29 and 0.52, respectively), and non- significant deviation from regression, indicating that performance of these cultivars could not be predicted under unfavourable environments. In this study, none of the cultivars showed regression coefficient equal to one or significant deviation from regression, indicating that no cultivar had average stability for this trait in all the three environments studied. The high amount of total sugars in environments E1 and E2 in our investigation could be attributed to low temperature (4.4°C), along with occurrence of frost during the vegetative phase and tuber development. Studies by Uppal et al (2003) also indicated that cvs. Kufri Chipsona-1and Kufri Chipsona-2 contained the lowest amount of total sugars (362 and 367mg/ 100g fresh weight, respectively). Cultivars Kufri Lauvkar, Kufri Chipsona-1, Kufri Chipsona-2 and Russet Nor x 97-ES-33 had lesser amount of reducing sugars than the Mean in all the three environments (Table 4). Persual of pooled data also showed that cvs. Kufri Lauvkar, Kufri Chipsona-1, Kufri Chipsona- 2 and Russet Nor x 97-ES-33 had significantly lower quantities of reducing sugars than the pooled Mean. ‘Kufri Chipsona-1’ had the lowest amount of reducing sugars (75.74mg/100g fresh weight), followed by ‘Kufri Chipsona- 2’ (81.94mg/100g fresh weight), ‘Russet Nor x 97-ES-33’ (165.88mg/100g fresh weight) and ‘Kufri Lauvkar ’ (202.90mg/100g fresh weight). Kumar et al, (2003) also reported reducing sugars to vary from season to season, and cool weather (1-5°C) led to an increase in sugar levels. This variation could be attributed to variation in crop durations under different environments. Cultivars Kufri Chipsona-1 and Kufri Lauvkar showed the content of reducing sugars within permissible limits, regression coefficient of less than one, and a non-significant deviation from regression, indicating suitability of these genotypes for cultivation under unfavorable environmental conditions. Gaur et al (1999) reported that potatoes grown in North-Western plains contained relatively low dry-matter and higher amounts of reducing sugars (which were attributed to the comparatively low temperature prevalent during crop maturation). ‘Kufri Chipsona-1’ had significantly less amounts of total phenols than the Mean value under environment E1. However, in the case of E2, cvs. Kufri Lauvkar and Kufri Chipsona-1 showed significantly lower amounts of total phenols than the Mean value. In the case of E3, cvs. Kufri Anand, Kufri Lauvkar, Kufri Chipsona-2 and Kufri Ashoka Table 4. Mean , regression coefficient (bi) and deviation from regression (S2di) for levels of reducing sugars (mg/100g fresh weight) in potato during the autumn season 2005-2006 Sl. Genotype E1 E2 E3 Overall bi S 2di No. Mean 1. Kufri Badshah 456.47 433.22 403.48 431.05 0.52 263.99 2. Kufri Anand 340.54 234.52 238.95 271.34 1.29 240.20 3. Kufri Chandramukhi 341.08 230.29 212.57 261.31 1.52 3.61 4. Kufri Bahar 473.99 307.78 312.98 364.92 2.03 537.60* 5. Kufri Lauvkar 211.36 202.72 194.62 202.90 0.17 17.22 6. Kufri Chipsona-1 103.22 77.76 46.24 75.74 0.56 293.18 7. Kufri Chipsona-2 102.08 94.92 48.81 81.94 0.45 820.55** 8. Kufri Ashoka 320.86 282.79 308.91 304.19 0.27 451.78* 9. Kufri Jawahar 402.15 298.87 267.36 322.79 1.53 61.12 10. Russet Nor x 97-ES-33 253.82 124.50 119.33 165.88 1.65 147.58 Mean 300.56 228.74 215.35 248.21 CD (5%) 30.60 24.99 21.08 24.99 SE of bi = 0.26 CV 7.19 5.87 4.95 *Significant at 5%; **Significant at 1% J. Hortl. Sci. Vol. 10(1):57-63, 2015 Prabhjot Kaur et al 61 showed significantly less amounts of total phenols than the Mean value (Table 5). From pooled analysis, cv. Kufri Lauvkar alone had a lower Mean of total phenols (37.56mg/ 100g fresh weight) than the pooled Mean. Though some of the cultivars showed a regression coefficient close to one (Kufri Anand, Kufri Ashoka and Kufri Jawahar), deviation from regression in their case was significant, thereby indicating poor stability of these cultivars for this trait. However, these values are higher than those reported by Marwaha (1999) in hybrids MP/90-94 (25.6mg), MP/91-G (27.1mg) and MP/90-83 (30.1mg) on per 100g fresh weight basis. In the environment E1, cv. Kufri Anand (0.06) alone had significantly less activity of polyphenol oxidase than the Mean value (0.08). In the case of E2, cvs. Kufri Badshah and Kufri Chipsona-2 had significantly less value for polyphenol oxidase activity than the Mean value (0.08). However, none of the cultivars showed significantly less value of polyphenol oxidase than the Mean value in environment E3 (Table 6). Analysis of pooled data indicated that cv. Kufri Chipsona-2 alone had on overall Mean (0.06) of polyphenol oxidase similar to the pooled Mean (0.06). However, Uppal (1999) reported that polyphenol oxidase activity was the highest in tubers of cv. Kufri Sutlej, and lowest in cv. Kufri Jawahar. In the environment E1, cvs. Kufri Chipsona-1 and Kufri Chipsona-2 produced chips of acceptable colour (each having a colour score of 2). In environment E2, cvs. Kufri Chipsona-1, Kufri Chipsona-2 and Russet Nor x 97-ES-33 produced chips of acceptable colour (2.00, 2.00 and 2.67 score, respectively). However, cvs. Kufri Lauvkar, Kufri Chipsona-1, Kufri Chipsona-2 and Russet Nor x 97-ES-33 Table 6. Mean , regression coefficient (bi) and deviation from regression (S2di) for polyphenol oxidase (IU) in potato during autumn season, 2005-06 Sl. Genotype E1 E2 E3 Overall bi S 2di No. Mean 1. Kufri Badshah 0.08 0.04 0.05 0.06 1.47 0.00 2. Kufri Anand 0.06 0.05 0.07 0.06 -0.22 0.00 3. Kufri Chandramukhi 0.07 0.06 0.05 0.06 0.96 0.00 4. Kufri Bahar 0.09 0.06 0.06 0.07 1.13 0.00 5. Kufri Lauvkar 0.09 0.08 0.05 0.07 1.43 0.00 6. Kufri Chipsona-1 0.09 0.08 0.06 0.08 0.92 0.00 7. Kufri Chipsona-2 0.08 0.04 0.05 0.06 1.32 0.00 8. Kufri Ashoka 0.09 0.08 0.05 0.07 1.58 0.00 9. Kufri Jawahar 0.08 0.09 0.05 0.07 1.39 0.00 10. Russet Nor x 97-ES-33 0.08 0.07 0.07 0.07 0.02 0.00 Mean 0.08 0.06 0.05 0.06 CD (5%) 0.02 0.02 0.01 0.01 SE of bi = 0.67 CV 19.16 27.53 36.70 *Significant at 5%; **Significant at 1% Table 5. Mean , regression coefficient (bi) and deviation from regression (S2di) for total amount of phenols (mg/100g fresh weight) in potato during the autumn season 2005-2006 Sl. Genotype E1 E2 E3 Overall bi S 2di No. Mean 1. Kufri Badshah 64.00 39.67 35.00 46.22 1.12 0.86 2. Kufri Anand 59.33 44.33 27.67 43.78 1.07 62.77** 3. Kufri Chandramukhi 58.33 38.00 37.33 44.56 0.85 7.65* 4. Kufri Bahar 74.00 50.00 40.33 54.78 1.25 4.86 5. Kufri Lauvkar 56.33 26.33 30.00 37.56 1.13 48.22** 6. Kufri Chipsona-1 54.33 34.33 38.00 42.22 0.72 28.67** 7. Kufri Chipsona-2 59.67 38.33 29.00 42.33 1.13 5.84* 8. Kufri Ashoka 59.00 41.67 28.33 43.00 1.07 30.31** 9. Kufri Jawahar 57.67 40.33 33.33 43.78 0.90 2.57 10. Russet Nor x 97-ES-33 56.00 36.67 37.67 43.44 0.76 13.22** Mean 59.86 38.96 33.66 44.16 CD (5%) 4.00 3.00 2.67 6.72 SE of bi = 0.23 CV 5.28 3.97 3.53 *Significant at 5%; **Significant at 1% J. Hortl. Sci. Vol. 10(1):57-63, 2015 Evaluation of potato genotypes for processing traits in late autumn 62 Table 7. Mean , regression coefficient (bi) and deviation from regression (S2di) for chip colour (score) in potato during the autumn season 2005-2006 Sl. Genotype E1 E2 E3 Overall bi S 2di No. Mean 1. Kufri Badshah 6.33 5.67 5.00 5.67 1.25 0.00 2. Kufri Anand 5.67 4.67 4.33 4.89 1.25 0.07 3. Kufri Chandramukhi 5.33 4.67 3.67 4.56 1.56 0.02 4. Kufri Bahar 5.33 5.67 4.67 5.22 0.62 0.30 5. Kufri Lauvkar 4.67 3.67 3.00 3.78 1.56 0.02 6. Kufri Chipsona-1 2.00 2.00 1.33 1.78 0.62 0.07 7. Kufri Chipsona-2 2.00 2.00 1.33 1.78 0.62 0.07 8. Kufri Ashoka 5.33 5.33 5.67 5.44 -0.31 0.02 9. Kufri Jawahar 5.33 4.67 4.00 4.67 1.25 0.00 10. Russet Nor x 97-ES-33 4.33 2.67 2.67 3.22 1.56 0.46* Mean 4.30 4.10 3.57 4.10 CD (5%) 1.81 0.92 1.07 0.48 SE of bi = 0.43 CV 11.59 13.02 11.77 *Significant at 5% produced chips of acceptable colour (score ≤ 3.0) in environment E3 (Table 7). Potatoes grown in a cool climate, particularly in areas where night-temperature drops below 10°C during the last month before harvest, are found not suitable for processing (Ezekiel et al, 1999). Pooled data analysis indicated that cvs. Kufri Chipsona-1 and Kufri Chipsona-2 produced chips of acceptable colour. ‘Kufri Chipsona-1’ and ‘Kufri Chipsona-2’ produced chips of excellent quality and light colour (score of 1.78 each). Pandey et al (2005) reported that in a late-planted crop at Modipuram, acceptable quality chips were produced only in cv. Kufri Chipsona-1. This cultivar produced light- coloured chips at all the stages of harvest and locations in North-Western and West-Central Indian plains (Pandey et al, 2005). Among the three environments studied, 120 days’ crop duration (E3) yielded the highest total tuber-yield (q/ ha) and processing-grade yield (q/ha), followed by E2 (100 days’ crop duration) and E1 (80 days’ crop duration) (Table 1). Besides total tuber-yield, most genotypes in group E3 exhibited high dry-matter content and low levels of reducing sugars, compared to that in the other environments, and, these are desirable attributes for processing. Though in the environment E1, cv. Kufri Ashoka yielded significantly higher (151.03 q/ha) than Mean, it had low dry-matter content. Therefore, this was unsuitable for processing purposes, but was suitable for table-purpose. In E2, cv. Kufri Chipsona-1 and Kufri Chipsona-2 had high yield, high dry-matter content and low amounts of reducing sugars. Therefore, these cultivars are suitable for processing. In the environment E3, cvs. Kufri Chipsona-1 and Kufri Chipsona-2 were found to have high tuber-yield, high dry-matter content, low levels of reducing sugars, and low amounts of total phenols. Also, both of these cultivars produced chips of acceptable colour in all the three environments. The potential of cvs. Kufri Chipsona-1 and Kufri Chipsona-2 is not fully exploited due to occurrence of frost at the vegetative stage of the crop. Kumar et al (2004) documented that 120 days’ crop duration was most suitable for Kufri Chipsona-1 and Kufri Chipsona- 2 in the spring season crop. From stability analysis data, it is concluded that cv. Kufri Chipsona-2 was stable for total tuber-yield in all the three environments. Therefore, cv. Kufri Chipsona-2 is recommended for cultivation for all the three crop durations to produce potatoes for the processing industry. REFERENCES Eberhart, S.A. and Russel, W.A. 1966. Stability parameters for comparing varieties. Crop Sci., 6:36-41 Ezekiel, R., Verma, S.C., Sukumaran, N.P. and Shekhawat, G.S. 1999. A guide to potato processors in India. Tech. Bull., 48, pp. 1-39, Central Potato Research Institute, Shimla, H.P., India Gaur, P.C., Singh, S.V., Pandey, S.K., Marwaha, R.S. and Kumar, D. 1999. Kufri Chipsona-2: a new, high dry- matter potato variety for chipping. Curr. Sci., 76:722- 724 Kumar, D., Singh, S.V. and Kumar, D. 2003. Chemical maturity of potato processing cultivars grown in Western Uttar Pradesh. J. Indian Potato Assoc., 30:225-232 Kumar, R., Pandey, S.K., Uppal, D.S. and Marwaha, R.S. 2004. 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Vol. 10(1):57-63, 2015 Evaluation of potato genotypes for processing traits in late autumn