Registration of upland cotton recombinant inbred lines MS-4857 and MS-4878 with resistance to root-knot nematode and reniform nematode

The root-knot nematode (RKN; Meloidogyne incognita Kofoid & White) and reniform nematode (RN; Rotylenchulus reniformis Linford & Oliveira) are serious pathogens of upland cotton (Gossypium hirsutum L.) that significantly affect yield and fiber quality annually. Here, we describe two upland cotton germplasm lines that have combined resistance to RKN and RN while maintaining good yield and fiber quality traits. Upland germplasm lines MS-4857 (Reg. no. GP-1147, PI 704481) and MS-4878 (Reg. no. GP-1148, PI 704482) are F₆ recombinant inbred lines from a cross between M240 RNR (RKN resistant) and MT2468 Ren1 (moderately RN resistant). These lines are highly resistant to RKN and show ∼30% fewer RN eggs g⁻¹ root than the MT2468 Ren1 parent due to significantly improved root system development compared with MT2468 Ren1. Yield and fiber quality traits are equivalent or superior to the parental lines. The upland-derived RN resistance in these lines provides a valuable alternative source of resistance to cotton breeding programs, especially in combination with high-level RKN resistance.