Study of some characteristics in raspberry breeding: rust resistance, earliness and fruit colour

H. Novo, F.R. Luz, M. Mota, P.B. Oliveira
Integrated in the raspberry breeding program implemented by INIAV, I.P. in partnership with Beirabaga company, three crosses were made to introduce desirable traits in a high-quality cultivar (female parent) with commercial potential, developed by the program. From the cross aimed at introducing resistance to late leaf rust disease (Thekopsora americana), 773 previously inoculated plants were evaluated for disease severity, in the greenhouse screening phase. Lowest and highest registered values were 0.2 and 46.8%, respectively. From those, 78 (10.1%) plants with a maximum severity of 5% were selected, to be installed in the field. The field assessment showed significant differences (p<0.05) in disease severity between the three families, the female parent and the resistance donor parent, which might indicate that some degree of resistance was transmitted to the offspring. From the cross meant to segregate for earliness, 1827 plants were evaluated in the field, from which 242 (13.2%) were first harvested up to six weeks prior to the female parent. The early individuals comprised 12 earliness groups, taking from 13 to 18 weeks from plantation to harvest of the king fruit, requiring 1360 to 1926 GDD (BT5°C). As in the first cross, this second one was successful in producing genotypes with potential to be selected to the next selection stage. The third and last cross was meant to produce offspring showing fruits of lighter colour than that of the fruits of the female parent. From 95 individuals that were evaluated, only 5 exhibited fruits whose measured colour parameters (L*, a*, b*, C*, ) showed significant differences (p<0.05) when compared to those of the female parent. These differences translate into fruit colours that meet the outlined goals, in particular individual 449, which exhibited fruits with the highest lightness value (L*449=43.6) and the third highest value for chroma (C*FP=49.4).
Novo, H., Luz, F.R., Mota, M. and Oliveira, P.B. (2024). Study of some characteristics in raspberry breeding: rust resistance, earliness and fruit colour. Acta Hortic. 1388, 313-322
DOI: 10.17660/ActaHortic.2024.1388.46
Rubus idaeus, Thekopsora americana, early production, CIE variables, early-stage selection

Acta Horticulturae