|
Data from 1996 replicated field trials averaged across 6 locations evaluate the combining abilities of new corn inbreds. Eleven advanced-generation (S8) inbreds were evaluated in topcrosses to 8 single-cross testers (including only public sector inbreds). Inbreds ND275, ND269, and ND301 were included as very-early, early, and intermediate maturity checks for comparing combining abilities. The new inbreds seem promising for use as parents for producing 65 to 85 RM hybrids. Three elite commercial hybrids of 75 to 80 RM (Terra brand E804, Pioneer brand 3963, and Mycogen brand 1376) also were included in the tests. PVPA applications have been filed for these inbreds.
Inbred ND280 seems to be the best of the new lines. ND280 was derived from a cross of an S0 plant from the synthetic breeding population, NDSB(FS)C3 to the related line cross (ND245xND252) via self pollination over 9 generations with concurrent selection for plant stature, plant health, ear characteristics, and leaf growth rates. NDSB(FS)C3 was developed from NDSB [Cross (1980), (Crop Sci. 20:418)] via reciprocal full-sib selection using NDSA as the tester population. Hybrids with ND280 averaged significantly higher grain yields and yield for maturity (performance index) than all other lines except ND301 (Table 1). ND280 averaged significantly higher general combining ability for higher test weights and lower stalk lodging percentages than ND301. ND280 silks about 6 days later than ND246 and produces very tall plants that average 2 ears per plant. Averaged across 2 locations in 1994, ND280 produced significantly higher inbred yields than any of 19 check inbreds (ND280 yielded 90 bu/a compared to 59 bu/a for CM105, the highest yielding check; 42 bu/a for ND257; 29 bu/a for ND246; 24 bu/a for A654; etc.). Because ND245, ND252, and ND246 are closely related sister lines, ND280 should produce good hybrids with lines that combine well with ND246. The S0 parent is from a population developed using NDSA as a tester, so ND280 should combine well with lines derived from NDSA (or NDSK) such as ND277, ND265, or ND272. This line is almost unrelated to Stiff Stalk Synthetic, so test crosses to Stiff Stalk lines are recommended. ND280 in a few hybrid combinations produced 80 RM three-way hybrids with performance similar to elite commercial single-cross hybrid checks (Table 2).
Inbred ND281 was derived from the synthetic breeding population, NDSAB(MER)C5 via self pollination over 9 generations with concurrent selection for plant stature, plant health, ear characteristics, and leaf growth rates. NDSAB(MER)C5 was developed from NDSAB [Cross (1983), (Crop Sci. 23:1227)] via modified ear-to-row selection. ND281 produced general combining abilities equivalent to the check lines for grain yield (Table 1). It produced yield for maturity ratios similar to ND269 and ND275. ND281 is a tall inbred that silks about 3 days later than ND246 and produces inbred yields similar to CM105. Test crosses to Stiff Stalk lines are recommended because NDSAB(MER)C5 is unrelated to Stiff Stalk Synthetic. ND281 in hybrid combinations produced two 85 RM three-way hybrids with perfomance similar to hybrids with ND269 (Table 2).
Inbred ND282 was derived from the synthetic breeding population, NDSB(FS)C4 via self pollination over 10 generations with concurrent selection for plant stature, plant health, ear characteristics and leaf growth rate. NDSB(FS)C4 was developed from NDSB [Cross (1980), (Crop Sci. 20:418)] via reciprocal full-sib selection using NDSF [Cross (1983), (Crop Sci. 23:1227)] as the tester population. Hybrids with ND282 averaged significantly lower grain moisture at harvest than any hybrid lines in Table 1. Its combining ability for performance index was equivalent to ND269 and ND275. This inbred appears capable of producing 65 to 75 RM hybrids. ND282 is a tall inbred that silks about 2 days later than ND246 with inbred yields similar to CM105. Since the parent population was produced using NDSF as a tester, this inbred line should combine well with lines derived from NDSF. ND262, ND263, ND264, and ND274 are released lines from NDSF. Test crosses to Stiff Stalk lines and lines related to ND246, such as ND280, are recommended. ND282 hybrid combinations produced two 70 RM three-way hybrids with better performance indices than hybrids with the very-early check inbred, ND275 (Table 2).
Table 1. Combining ability effects for 3 new and 3 standard inbreds averaged across 6 ND locations and 8 single cross testers for each line.
Inbred |
Grain moisture |
Grain yield |
Root lodging |
Stalk lodging |
Plant population |
Test wt. |
Performance index + |
(%) |
(bu/a) |
(%) |
(%) |
(plants/a) |
(lb/bu) |
(%) |
|
| ND280# | 0.00 |
13.19 |
-0.10 |
-0.24 |
701 |
1.12 |
15.3 |
| ND301 | 0.33 |
8.34 |
0.01 |
1.76 |
16 |
-0.90 |
8.9 |
| ND282 # | -1.47 |
-5.28 |
-0.15 |
0.52 |
-95 |
-0.82 |
1.3 |
| ND269 | 1.34 |
6.50 |
-0.01 |
-1.47 |
713 |
0.75 |
0.3 |
| ND281 # | 1.26 |
4.82 |
0.00 |
0.94 |
592 |
-0.13 |
-0.2 |
| ND275 | -0.06 |
-1.19 |
0.49 |
-1.96 |
597 |
0.56 |
-0.7 |
| LSD (0.05) | 0.82 |
6.25 |
NA |
1.66 |
1160 |
1.12 |
8.5 |
| Mean+ | 25.58 |
87.54 |
0.36 |
5.13 |
21484 |
53.14 |
101.1 |
+Averaged across 8 testers and 6 ND locations for 15 inbreds included in the test.
#Data in bold indicate the new Inbred line.
Table 2. Average performance of 2 selected 3-way hybrids with each of 3 new inbreds and 3 standard inbreds compared with 2 elite 75 to 80 RM commercial hybrids across 6 ND locations in 1996.
Inbred |
Grain moisture |
Grain yield |
Root lodging |
Stalk lodging |
Plant population |
Test wt |
Performance+ index |
(% ) |
(bu/a) |
(%) |
(%) |
(plants/a) |
(lb/bu) |
(%) |
|
| Comm. hybrids | 25.18# |
113.24 |
0.03 |
2.56 |
22125 |
52.62 |
131.5 |
| ND280 | 25.50 |
107.01 |
0.78 |
5.48 |
22261 |
53.88 |
124.3 |
| ND281 | 27.14 |
104.83 |
0.20 |
5.54 |
22449 |
53.09 |
114.1 |
| ND282 | 21.38 |
85.89 |
0.35 |
4.45 |
21918 |
52.92 |
120.7 |
| ND269 | 28.08 |
103.02 |
0.29 |
2.83 |
23062 |
53.21 | 107.1 |
| ND301 | 25.09 |
106.69 |
0.20 |
10.74 | 23628 |
52.38 |
123.7 |
| ND275 | 25.12 |
87.61 |
1.00 |
4.96 |
22945 |
54.70 |
103.6 |
| LSD (0.05) | 1.38 |
10.95 |
1.54 |
3.30 |
1966 |
1.91 |
13.7 |
+Performance index = [(Yield/test-site mean)/(moisture/test-site mean)] x100.
#Values in bold are significantly different from the commercial checks.
Corn Inbred Lines - 1998 Releases
The following inbred lines (that survived preliminary screening evaluations for general combining ability at the S6 generation) were tested in 8 hybrid combinations each at 5 locations in 1997 (except for ND284 which was tested in 1996). They were compared to check inbreds ND301, ND277 and ND278 (Tables 1 and 2). ND301 is an older inbred with excellent yield for maturity but only average resistance to stalk breakage. ND277 and ND278 were the newest yellow dent inbreds at the time the crosses were made. (NDSU released ND277 and ND278 in 1996 and received PVPA certificates in 1997). ND277 produces hybrids with very early maturity and ND278 produces hybrids with intermediate maturity. Three hybrids with ND280, the inbred with the best performance index of inbreds tested in 1996 (Tables 3 and 4), were included as checks in a yield test conducted at 2 locations in 1997 (Table 5). ND285, ND287, ND289, ND288 and ND286 were initially evaluated for combining ability in 1995 while ND285, ND286 and ND287 were included as checks in the 1996 trial (Table 6). Data on each of these inbreds were collected at 3 locations in 1997. PVPA applications have been filed.
Inbred ND285, derived from synthetic NDSCD(MS)C1, a new breeding source population developed at NDSU, showed significantly higher general combining ability for yield for its maturity (performance index) than ND278 (Table 1). ND285 showed significantly improved general combining ability for (1) stalk breakage resistance compared to ND301 and ND277; (2) grain yield compared to ND277; (3) ear moisture at harvest compared to ND301 and ND278; and (4) test weight compared to ND301 and ND278. ND285 showed high combining ability for low moisture at harvest, high yield for maturity, low stalk breakage and high test weight in tests conducted in 1995 and 1996 (Table 6). In a separate test at 2 locations in 1997, 2 hybrids with ND285 showed significantly lower harvest moisture, stalk lodging and yield for maturity than 3 check hybrids with ND280 (Table 5).
Inbred ND287 resulted from selfing progeny of the hybrid (ND245 x ND252) crossed to an S1 plant from breeding population, NDSL. General combining ability for ND287 was significantly higher for (1) grain yield compared to ND277; (2) stalk lodging resistance compared to ND301 and ND277; (3) ear moisture at harvest compared to ND301; and (4) test weight compared to ND301 and ND278. ND287 showed high combining abilities for stalk lodging resistance, performance index and test weight in 1995 and 1996 trials (Table 6). This inbred is related to ND280 and showed significantly higher combining abilities for grain yield, stalk lodging and performance index in 1997 (Table 5).
Inbred ND289 was derived from NDSA(FS)C4, a population produced using reciprocal full-sib selection with NDSB(FS)C4 as the tester. ND289 showed significantly improved general combining ability for (1) stalk breakage resistance compared to ND301; (2) ear moisture at harvest compared to ND301 and (4) test weight compared to ND301 and ND278. ND289 showed high combining ability for resistance to stalk breakage, performance index and test weight in 1995 (Table 6) and was significantly better than ND280 in 1997 for low harvest moisture, resistance to stalk breakage and performance index (Table 5).
Inbred ND288 resulted from selfing the progeny of the hybrid between S0 plants from NDSF(FS)C1 and NDSB(FS)C1. ND288 showed significantly improved general combining ability for (1) stalk breakage resistance compared to ND301 and ND277; (2) ear moisture at harvest compared to ND301 and (3) test weight compared to ND301 and ND278. ND288 showed high combining ability for stalk breakage resistance, low harvest moisture, performance index and test weight in 1995 (Table 6) and was significantly better than ND280 in 1997 for low harvest moisture (Table 5).
Inbred ND286 was derived from synthetic NDSCD(MS)C3, a new breeding source population developed at NDSU using 3 cycles of mass selection for yield on unlodged plants. General combining ability for ND286 was significantly higher for (1) grain yield compared to ND277 and ND278; (2) stalk lodging resistance compared to ND301 and ND277 and (3) test weight compared to ND301 and ND278. ND286 hybrids showed high yield and performance indices in 1995and 1996 trials (Table 6) and significantly lower stalk breakage than ND280 hybrids in 1997 (Table 5).
Inbred ND284 was derived from synthetic NDSM, a new breeding population developed at NDSU. This inbred was tested in 8 hybrid combinations across 6 locations in 1996. Due to a lack of data needed for PVPA application in 1997, it was not released until 1998. ND284 showed significantly better general combining ability for (1) low harvest moisture than ND269, ND301 and ND281; (2) grain yield than ND275 and ND282; (3) stalk lodging resistance than ND301 and (4) performance index than ND282, ND269, ND281 and ND275 (Table 3).
