Suitability of Elite Clones of Potato for Short Duration and Heat Tolerant Capabilities and their Characteristics

Collaborative studies were conducted at Potato Technology Centre, Shamgarh, Karnal, India and in different districts of Haryana during 2018-19 to identify suitable varieties for semi-arid, agro-ecology of Haryana. First experiment was conducted at Potato Technology Centre, Karnal during 2018-19 to evaluate the clones/ varieties at for short duration maturity possibilities. The treatments included seven clones of potato from CIP and five popular varieties CPRI. The experiment was laid out in randomized block design with three replications. Sowing was done on 24 October, 2018 at a spacing of 60 cm x 20 cm. Dehaulming of potato crop was done at 75 days after sowing (DAS). Second experiment was conducted with 7 most promising CIP clones along with five popular varieties of CPRI in five selected districts of Haryana (Karnal, Kurukshetra, Rohtak, Sirsa and Mahendergarh) was laid out to explore the location specific clones. The experiment was laid out in randomized block design with three replications at each location. Sowing was done in October, 2018 at Karnal, Kurukshetra and Rohtak, and in November, 2018 at Mahendergarh and Sirsa. Spacing was 60 cm x 20 cm. Dehaulming of potato crop was done at 90 DAS. By dehaulming at 75 DAS, maximum tuber yield was recorded with Kufri Mohan (40.6 t/ha), followed by CP 4393 7008 and Kufri Khyati (31.6 t/ha), indicating their suitability for short duration maturity. When dehaulming of potato was done at 90 DAS, variety Kufri Mohan resulted in highest tuber yield and ranked one in Karnal, Kurukshetra and Sirsa (40.6-50.3 t/ha); Kufri Khyati in Mahendergarh (42 t/ha) and CP 4404 7015 in Rohtak (38.6 t/ha). The tuber yield of CP 4393 7008 and CP 4395 7010 was almost same in both the trials, indicating early maturity of these clones along with characteristics of late maturity. Highest dry matter (19%) was recorded in clones CP 4397 7011 and CP 4404 7015 with highest specific gravity (1.070) and total solid contents (19.2%), suggesting both the clones to be good as processing varieties. Characterization of elite clones of potato was also done.


INTRODUCTION
Potato is a major world food crop, next in production only to Maize, Rice & Wheat. In India potato is being cultivated on an area of 2.14 million ha with production of 51.3 million tons (IASRI, 2019), which is second only to China. Potato has wide flexibility in planting and harvesting time that help adjusting the crop in various intensive cropping systems without placing excessive pressure on scarce land and water resources. To meet the needs of the increasing population of the country, the production of potato in the country has to be increased to 122 million tons by 2050 and the productivity from 23 tons to 35 tons per hectare (CPRI, 2015). To meet this production target there are plenty of challenges ahead for India in general and Haryana in particular. These include seed potato production under climate change scenario, the development of climate smart cultivars for the changed climate and increase in productivity by making quality seed available to the farmers. Further, Haryana requires potato varieties of short duration, early heat tolerance and virus resistance, in order to fit in the rice-wheat crop system. The early harvest of short duration varieties would provide a productive window to produce an additional winter crop-such as wheat or cash crops (vegetables). The presently available short duration varieties have low storability due to high degeneration rate and poor keeping quality due to low dry matter. Hence, studies were initiated at Potato Technology Centre, Shamgarh, Karnal, India in collaboration with International Potato Centre (CIP), Central Potato Research Institute (CPRI) to identify suitable varieties for semiarid, agro-ecology of Haryana for creating better income opportunities for the farmers. Genetic resources exchanged from CIP and CPRI were evaluated to develop improved short duration, early heat tolerant, salinity tolerant and virus resistant robust varieties to assist farmers in getting a remunerative price for their produce. Experiments were planned at PTC, Shamgarh with the objective to select robust, short duration, early heat tolerant and virus resistant potato varieties for rice-wheat production systems; strengthen institutional capacity for quality seed production at farmlevel and participatory multiple-environment selection of climate smart varieties.

MATERIALS AND METHODS
Five districts namely Karnal, Kurukshetra (Potato growing belt) and Mahendergarh, Rohtak and Sirsa (non-potato growing belt) were selected for their suitability for seed potato production and growing of processing varieties. The clones from CIP were evaluated in the two experiments during 2018-19, the details of which are given below.

Experiment 1: Evaluation of potato clones dehaulmed at 75 days
The experiment was conducted at PTC, Karnal during 2018-19 to evaluate the clones/ varieties at for short duration maturity possibilities. The treatments included seven clones of potato from CIP (CP 4388 7003, CP4393 7008, CP 4395 7010, CP 4397 7011, CP 4404 7015, CP 4406 7017, CP 4197 7019) and five popular varieties (Kufri Pukhraj, Kufri Khyati, Kufri Mohan, Kufri Chipsona 1, Kufri Lima) from CIPRI. The experiment was laid out in randomized block design with three replications. Sowing was done on 24 October, 2018 at a spacing of 60 cm x 20 cm. Whole tubers were used as seed for sowing. The plot size was 2.4 m x 3.0 m. Dehaulming of potato crop was done at 75 days after sowing (DAS), and tubers were excavated 2 weeks after dehaulming. The data on number of tubers, number of marketable tubers, tuber yield and marketable tuber yield were recorded from harvested plot area and concerted to per hectare basis.
The dry matter (%), specific gravity (g/cc) and total solid content (%) of CIP clones was done through Goodrich Factory from Karnal for the Karnal harvested samples in year 2018-19, for characterization of the clones. The experiment was laid out in randomized block design with three replications at each location. Sowing was done in October, 2018 at Karnal, Kurukshetra and Rohtak, and in November, 2018 at Mahendergarh and Sirsa due to conditions of high temperature and sandy soils in these districts. Spacing was 60 cm x 20 cm with use of whole tubers as seed. The gross plot size was 2.4 m x 3.0 m. Dehaulming of potato crop was done at 90 DAS, and tubers were excavated 2 weeks after dehaulming. The data on number of tubers, number of marketable tubers, tuber yield and marketable tuber yield were recorded from net plot area and concerted to per hectare basis.

Experiment 2. Evaluation of potato clones dehaulmed at 90 DAS
The data were subjected to the analysis of variance (ANOVA). The significant treatment effect was judged with the help of 'F' test at the 5% level of significance, and the significant treatment effect was judged with the help of 'F' test at the 5% level of significance (Cochran & Cox, 1957). The results are in agreement with other researchers that tuber yield varies with variety, location and genotypes x environment interaction (Pandey et al. 2004;Kumar et al., 2007;Elfinesh, 2008;Gebreselassie et al., 2016;Preetham et al., 2018).

Comparison of 75-and 90-days dehaulmed potato
The tuber yield of CP 4393 7008 and CP 4395 7010 was almost same in both the trials, indicating early maturity of these clones along with characteristics of late maturity (Fig. 1). However, the short duration popular variety Kufri Pukhraj showed increase in the yield by late dehaulming including Kufri Mohan to be suitable as late maturity cultivar. Therefore, these two clones CP 4393 7008 and CP 4395 7010 could be suitable candidates for short duration maturity situations.

Dry matter accumulation and physical properties of potato clones
Highest dry matter (19%) was recorded in two clones CP 4397 7011 and CP 4404 7015 which had highest specific gravity (1.070) and total solid contents (19.2%) ( Table  3). It suggested that both the clones were good as processing varieties.
Other physical properties of different elite clones of potato are given in Table 4, which could guide in selection of these clones for need based specific purpose.     Among varieties Kufri Mohan and Kufri Khyati were found suitable for early maturity and among the new elite clones CP 4393 7008 and CP 4395 7010 were found suitable for short duration maturity. Farmers could invest their earnings into a second winter harvest, helping them to improve the overall productivity of the cropping system. The clones (CP 4397 7011, CP 4404 7015) having higher dry matter and low sugar content were suitable for processing. Thus new elite clones of potato could help in increasing farmers' income.