The effects of screening for root mass in the seedling generation on the root mass in the tuber generation in the hybrid potatoes [Solanum tuberosum]

• Published in: Research Bulletin of the University Farm, Faculty of Agriculture - Hokkaido University (Japan) no. 31
• Main Authors: Kashiwagi, J. (Hokkaido Univ., Sapporo (Japan)), Iwama, K, Hasegawa, T, Nakaseko, K, Moki, N, Ichikawa, S
• Format: Journal Article
• Language: Japanese
• Published: 01.03.1999
• Subjects: ENSAYOS DE VARIEDADES; ESSAI DE VARIETE; HIBRIDOS; HYBRIDE; HYBRIDS; RACINE; RAICES; ROOTS; SOLANUM TUBEROSUM; VARIETY TRIALS
• ISSN: 0385-6445

The effects of screening for root mass in the seedling generation were investigated for two hybrid populations of potatoes. One is derived from the cross between Norin 1 (N, large root mass) and Konafubuki (K small root mass), and the other is from Benimaru (large root mass) and K. The seedlings derived from true seeds of the two populations (N x K, B x K) were grown in pots (pi 7 x 6 cm) in a greenhouse the autumn in 1995. Soils consisted of mixture of volcanic ash sandy roam soil, peat moss and sand (1:1:1 parts by volume). The 78 and 53 genotypes for N x K and B x K, respectively, were sampled at approximately six leaf stage. The root length (RL) was measured after the roots were washed in running water. The top of each plant was cut and inserted into the sand in the beds for rooting, then transplanted into a pot for further cultivation. The tubers harvested from the pot the winter in 1996 were planted in the field for propagation in 1996. In 1997, the 56 and 39 genotypes for N x K and B x K, respectively, were cultivated in the field on May 1 with a row width of 75 cm and hill distance of 40 cm. A combination of fertilizers at the rate of 1000 kg ha(-1) of 7-11-9 (N, P2O5, K2O) was applied before planting. The root, leaf, stem and tuber dry weight (DW) at maximum top growth stage and the tuber characteristics at harvest time were measured. 1. In the seedling generation, two populations showed different distributions of RL; i.e. bi-modal in N x K and continuous in B x K. The genotypes of each generation were classified into two groups (S class; short RL, L class; long RL) based on the boundary of RL of 8 m pl-1 in N x K and of 5 m pl(-1) in B x K. The segregation ratio of genotypes of S class and L class fitted 3 : 1 in N x K (0.50p0.75). 2. In both seedling and tuber generation, N x K population had both larger mean value and variability of RL or root dry weight (RDW) than the B x K population which was consistent with the order of RDW of the female parents. The heritability of RDW in the tuber generation was 61 % in both populations, being similar to the heritability of shoot and tuber DWs. 3. In the N x K population, the genotypes of L class had significantly larger RDW than those of S class in the tuber generation. In the B x K population, however, the difference between the S and L class was not detected. In the N x K population, the 67 % of the genotypes of L class, while the 22 % of the genotypes of S class, showed larger RDW than N in the tuber generation. In the B x K population, the genotypes with larger RDW than B were 22 % in both S and L class. The results indicate that using a variety or line of larger root mass as a parent of crossing, we can make a wider genetic variability of root mass in the offspring. Especially, in the population derived from N, it would be possible to get the genotypes with large root mass in the tuber generation by screening the root mass at the early stage in seedling generation