Development of 'TN16-520R1': A drought-tolerant soybean cultivar with glyphosate resistance

The glyphosate-tolerant soybean [Glycine max (L.) Merr.] line 'TN16-520R1' (Reg. no. CV-560, PI 703273) was released as a high-yielding cultivar by University of Tennessee Agricultural Research in 2018. TN16-520R1 is a BC4F2 cultivar derived from the recurrent parent 'Ellis', with drought tolerance and a maturity group (MG) of V-early. It has white flowers, gray pubescence, tan podwall, and a determinate growth habit. The seed has buff hila, is yellow with smooth seed coat, and contains 40% protein and 22% oil on a dry weight basis. TN16-520R1 has good resistance to lodging and good seed quality (1.8 and 1.6, respectively, on 1-5 scale), and a seed size of 11.8 g per 100 seed. Like Ellis, TN16-520R1 has performed competitively throughout much of the mid-South United States over several years, with testing occurring over a 6-year period in 100 environments. Further, TN16-520R1 is remarkably like the recurrent parent Ellis for yield, maturity, lodging, height, protein, and oil. Also, like Ellis, TN16-520R1 is resistant to stem canker [caused by Diaporthe phaseolorum (Cooke & Ellis) Sacc. var. caulivora K.L. Athow & R.M. Caldwell] and southern root-knot nematode [Meloidogyne incognita (Kofoid and White) Chitwood] and has field tolerance to frogeye leafspot [caused by Cercospora sojina (Hara)]. This combination of beneficial traits and broad adaptability make TN16-520R1 an excellent choice as a soybean cultivar for producers or a crossing parent for breeders. This study describes the development of a high-yielding soybean cultivar through backcross breeding. Drought tolerance is a distinguishing feature of TN16-520R1. TN16-520R1 possesses glyphosate resistance, which differs from the conventional recurrent parent.