Investigation of Genetic Diversity in Terms of Morphological, Phenological, and Quality Traits in Hybrids Obtained from the Crossbreeding of Two Improved Populations with Ten New Potato Cultivars in Spring Cultivation

Abstract
This experiment was carried out to investigate the genetic diversity in some morphological, phenological and qualitative traits in hybrids obtained from the crossing of two breeding populations with 10 new potato varieties in spring cultivation in the Ardabil region in 2019. Twelve genotypes were planted in three replications based on a randomized complete block design. The analysis of variance showed that the cultivars were significantly different in all studied traits. Cluster analysis divided the studied genotypes into three distinct groups. Therefore, the first group would be more appropriate if the selection target is based on yield, tuber weight, and starch percentage. The hybrids derived from Savalan♀ × Caeser♂ and Caeser♀× Savalan♂ crosses as well as cultivars of Liseta and Ribera, had the highest tuber yield (ranging from 36.63 to 39.97 ton.ha^-1) among the studied genotypes. But in terms of starch and tuber dry matter percentage, only hybrids derived from the Savalan♀ × Caeser♂ cross were among the top genotypes and appearance characteristics, especially in baking; in group D, the skin and the flesh was yellow, the shape of the tuber was round, the depth of the eye was superficial, stolon's length was short, the harvest time was average early and it had a perfectly floury texture to the chips. The hybrids derived from the Caeser♀× Savalan♂ cross had a flour texture suitable for the slice. Liseta and Ribera varieties had a relatively soft texture and were ideal for multipurpose use.
Introduction
In terms of nutritional importance and production, potato ranks third after wheat and rice, with an annual production of over 3.41 million tons in Iran. It is one of the four main food substances worldwide after wheat, rice, and corn. Thus, 5.2% of the daily energy consumed by the world’s population is supplied by potatoes. Given the increasing trend of the world’s population, which is expected to reach 9 billion by 2050, food security will be the most critical challenge for governments. Many potato cultivars are available; however, there is a dire need for new cultivars. New cultivars should have high yields with minimal input and possess characteristics that play a role in nutrition and health. They should also be suitable for the tuber morphology, tuber compounds, and solids. Given the importance and need of our country to identify potato cultivars and introduce high-yielding and adaptable cultivars to the climatic conditions of each region, this study aimed to evaluate the genetic diversity of some morphological, phenological, and quality traits in hybrids resulting from the crossbreeding of two improved populations with ten new potato cultivars in spring cultivation in the Ardabil region. The results can serve as a basis for breeding programs to introduce new cultivars compatible with spring cultivation regions.
 Materials and methods
Twelve genotypes, including hybrids obtained from the crossbreeding of two improved populations, along with ten new potato cultivars, were examined during the spring cultivation of 2019 in the Ardabil region. The experiment was conducted using a randomized complete block design with three replicates. Each genotype was planted in two rows, each 5 m long, with a distance of 75 cm between rows and 25 cm between the plants in the row. The planting depth of the tubers was considered to be 10 cm. Planting, maintenance, and harvesting operations were uniformly applied to all plots. The traits that were examined included the number of main stems per plant, plant height, number of tubers per plant, tuber weight per plant, tuber yield, dry matter percentage, and starch percentage.
Results and discussion
According to the results, the genotypes under investigation had significant differences in all traits which were studied. The Savalan cultivar had the highest plant height, whereas regarding the number of main stems Caruso and Savalan cultivars were noticeably higher. The hybrids resulting from the crossbreeding of the Savalan♀×Caeser♂, Caeser♀× Savalan♂, and Liseta and Savalan cultivars had the highest number of tubers and tuber weight per plant, as well as total tuber yield. The hybrids resulting from the Savalan♀×Caeser♂, Caruso, Crisps4all, and Savalan cultivars had the highest starch and dry matter percentages of the tuber. Generally, cultivars with higher dry matter content absorb less oil when fried; therefore, they are also better in terms of nutritional health. The heritability of the traits under study was estimated to be 72.66%–98.29%. The heritability of the tuber yield was 89.03%. The hybrids resulting from Savalan♀×Caeser♂, which were superior in yield and other desirable traits compared to other genotypes, had a yellow skin and flesh colour, round tuber shape, superficial eye depth, short stolon length, and medium early maturity time, and were in the D cooking group, which had a mealy texture suitable for chips.
 Conclusion
Based on the results of this study, the hybrids resulting from Savalan♀×Caeser♂, Caeser♀× Savalan♂, and the Liseta and Ribera cultivars, with an average of 36.63 to 39.97 tons per hectare, had the highest tuber yield among the genotypes under study. The hybrids obtained from Savalan♀×Caeser♂ had a mealy texture suitable for chips. The hybrids resulting from Caeser♀× Savalan♂ had a mealy texture suitable for frying, and the Liseta and Ribera cultivars had a relatively soft texture suitable for multi-purpose use.