TITLE:

 

The Effect of Cotton Varieties on Reproduction of Root-knot Nematode at AG-CARES, Lamesa, TX, 2001.

 

AUTHORS:

 

             Terry Wheeler (TAES) and John Gannaway (TAES), Associate Professor and Professor

 

RESULTS AND DISCUSSION:

 

A breeding nursery was established at AG-CARES in 2001 to screen germplasm for resistance to root-knot nematode. Breeding lines are selected by John Gannaway based on yield potential and fiber qualities. Roots of selected plants were examined for galling, and those with minimal galls and good yield potential were kept for more testing. During the winter, selected breeding lines are tested in the greenhouse with root-knot nematode, and those with significantly less galling than Paymaster (PM) HS-26 are planted into a small plot variety test the following spring. The small plot variety test (40' long x 2 rows wide) is sampled for root-knot nematode. A ginned sample from each harvested plot is used to calculate turnout. In 2001, the replicated test consisted of 2 nematode resistant checks (Acala NemX and LA887), 6 breeding lines selected by J. Gannaway in previous years, 10 varieties from Paymaster, 2 varieties from Deltapine (458BG/RR and 237 B), and one variety from Aventis (FiberMax 989), All-Tex (Atlas), Suregrow (215BR) and Stoneville (STX 9905, which is a BT and RR version from LA887).

 

There were two lines (LA 887 and 00T#CCC-6) which combined high yields and did not increase root-knot nematode over 10,000 per pint of soil. LA 887 has been discontinued as a variety, and 00T#CCC-6 is a selection by John Gannaway out of CA 2154. Varieties or breeding lines which yielded fairly well, but had higher levels of root-knot nematode included STX 9905, Suregrow 215BR, Deltapine 458 B/RR, Paymaster 2379RR, Fiber Max 989, Acala NemX and Paymaster 2326 BG/RR (Table 1).

 

 


Table 1. Reproduction of root-knot nematode and yield on breeding lines and varieties planted at AG-CARES in 2001.

 

Root-knot nematode

Lbs of

Variety

Per pint of soil

lint/a

PM 2280BG/RR

52,230 a

   887 c-h

PM 2200RR

50,640 a

   852 d-i

PM 1218BG/RR

40,485 ab

   866 d-i

PM 2167RR

39,105 abc

   815 f-i

All-Tex Atlas

34,860 a-d

   756 h-i

DP458BGRR

34,035 a-d

1,036 abc

FM 989

31,680 a-e

1,002 a-d

PM 2344BG/RR

22,560 b-f

   790 h-i

PM 2326BG/RR

19,575 c-f

   966 a-f

00T#CCC-4

18,630 c-f

   912 c-h

00T#CCC-5

17,880 c-f

   845 e-i

00T#CCC-13

16,485 d-f

   902 c-h

00T#CCC-2

15,555 d-f

   907 c-h

Suregrow 215BR

14,895 d-f

1,062 ab

STX 9905

14,280 d-f

1,121 a

Acala NemX

12,150 ef

   981 a-e

DP 237 B

11,955 ef

   842 e-i

PM 2379RR

11,115 ef

1,028 abc

PM 2326RR

10,410 ef

   918 b-g

PM 2266RR

10,155 ef

   716 i

PM HS-26

  9,970 ef

   808 h-i

00T#CCC-6

  7,500 f

   985 a-e

00T#CCC-1

  4,485 f

   782 h-i

LA887

  4,230 f

1,077 a

A fall root-knot nematode density from 1,000 to 5,000 is in a moderate damage category, and > 5,000 would be considered in a high damage category.