Valentina Dimitrova and Minka Koleva
Agricultural Academy, Field Crops Institute, 6200 Chirpan, Bulgaria
Dimitrova, V. & Koleva, M. (2023). Results from the testing of the new candidate cotton varieties No 457 and No 535. Bulg. J. Agric. Sci., 29 (1), 62–69
As a result of the selection for earliness, productivity and fiber quality, two new candidate cotton varieties No 457 and No 535 were obtained. The candidate variety No 457 was obtained by remote hybridization, No 535 – by intraspecific hybridization. In 2014 – 2017, both candidate varieties were included in competitive variety trials. In the IASAS (Exclusive Agency for Variety Testing, Approbation and Seed Control) they were tested in 2017 – 2018. The two candidate varieties combined productivity and high fiber quality, which make them very valuable for cotton breeding programs. The candidate variety 457 had high and stable performance by years. In seed cotton yield of 2380 kg/ha, on average for two years, it exceeded the two standards – Chirpan-539 and Avangard-264, respectively by 11.3% and 14.7%, the average standard by 13.0%. It also was superior to them in September harvest and in yield of the fiber/ha. The candidate variety 535, in the state variety testing, in seed cotton yield was inferior to Chirpan-539 variety (standard for productivity) of 3.1% and was equaled to Avangard-264. It exceeded both standards in yield of the fiber per hectare as a result of its high lint percentage. The two candidate varieties were distinguished by high fiber quality and in some respects they exceeded the two standards or were aligned with Avangard-264, the standard for fiber quality. Compared to the standard varieties, both candidate varieties had better fiber consistency (SCI) Index, greater Upper Half Mean Length, and better spectroscopy reflecting the difference RD. Candidate variety No 457 differed with a better fiber uniformity in length than the two standards, while No 535 differed with a finer and stronger fiber. Both candidate varieties are very valuable for the selection of cotton, for inclusion in crosses to improve the productivity and fiber quality of modern cotton varieties. The No 457 in 2020 was approved by the IASAS as a new cotton variety under the name Aida.