Table 3. Seed yield traits for the F2:7 RILs.

TWO THUMBS UP FOR YIELD TRAIT VARIATION IN WHITE LUPIN

S.L. Noffsinger and Edzard van Santen

Department of Agronomy and Soils, 202 Funchess Hall, Auburn University, AL 36849-5412ABSTRACT

A 'Tifwhite-78' derived line (indeterminate, low alkaloid, white flowers, small seed size) was crossed with 'Lucyanne' (determinate, low alkaloid, white flowers, large seed size). From a single F1 seed, 208 F2:7 recombinant inbred lines (RILs) were developed by single seed descent (SSD) in the greenhouse, and 6 plants per F2:7 RIL were hand-sown on October 25, 2002 at E.V. Smith Research Center in central Alabama, USA. Due to insect destruction of the mainstem in many lines that winter, the basal mainstem and branches developed at the same time and functioned like mainstems and branches. The growth habit range was very diverse (Fig. 1, 2), and 13 RILs were segregating for determinate vs. indeterminate growth in the F2:7 and F8. Growth habit variation better fit a 9:7 ratio with a two or more gene model; this also indicates that within a single cross, one could select out a broad range of growth habit types if needed. Mean seed weight and pod wall proportion, as well as yield trait variation with regard to growth habit classes will be discussed. The variation in agronomic traits should provide a good basis for beginning both genetic and yield studies.

OBJECTIVE

Examine agronomic traits in segregating RILs of winter-type white lupin.

INTRODUCTION

In any breeding program, genetic variation is necessary for progress in selection and to obtain genotypes which fit either the environment and/or the particular crop use. In the case of winter-type white lupin (Lupinus albus L.), multiple potential uses for this crop require selection for traits which meet the use of a particular variety, e.g. more severe determinate growth for a variety with uniform seed size for snacks and other types of human consumption vs. indeterminate growth with rapid regrowth for a deer forage variety (Noffsinger et al., 2006a). In this study, we examined 208 F2:7 RILs obtained from a single F1 seed for segregating agronomic traits.

MATERIALS AND METHODS

Original Cross

‘Tifwhite-78’ x ‘Lucyanne’ indeterminate determinate low alkaloid high alkaloid white flowers white flowers small to ave seed size large seed size

2002-03 EV Smith Research Ctr (Central AL)

208 F2:7 RILs* 6 seeds hand-sown, 1 replicate Sown October 25, 2002

2003-04 EV Smith Research Ctr (Central AL)

13 segregating 2002-03 RILs sown plant to plot 189 non-segregating 2002-03 RILs bulked for mainstem seed and hand-sown as F8

Also planted: ‘AU-Homer’ (cover crop, indeterminate) Deer_305 (indeterminate) Deer_310 (indeterminate) ‘Lucyanne’ XA100 (dwarf) 10 seeds/plot, 2 replicates Sown October 29, 2003

*In the greenhouse, F2:7 RILs were produced by SSD without the presence of pollinating insects.

CONCLUSIONS

Segregation for growth habit in 13 of the 208 F2:7  RILs and segregation in the following F8 lines (data not shown) indicates that one could obtain a better test for grain yield differences among growth habit types with segregating sister lines. In the past, scientists have used distantly related cultivars which had growth habit differences to examine grain yield differences.

The variation in agronomic traits should provide a good basis for beginning both genetic and yield studies, and future breeding.

RESULTS

The majority of the F2:7 RILS had mainstem damage caused by lupin fly (Hylemia lupini L.) on at least 1 or 2 plants, if not the entire 6 plants. Spraying the F8 with insecticides throughout the winter of 2003-04 seemed to eliminate the lupin fly problem, and resulted in a dramatic decrease in damaged mainstems.

Growth habit variation was beyond that predicted by previous assumptions of a 3:1 ratio (Fig. 1, Table 1 ; Noffsinger et al., 2006b), indicating not only that more than one locus is responsible for the growth habit trait, but also that one could obtain a continuous range of variation for growth habit if needed from a single cross. The stability of growth habit ratings in the 2 to 3.5 range was least stable from the F2:7  to F8 generations (Noffsinger et al., 2006b) although some individual RILs were stable in that range (data not shown).

The regression of growth habit type on main-stem chlorophyll meter readings (LSMEANS) for the F2:7 RILS provided a quadratic equation (y = 64.2 + 1.28x – 0.36x2; R2 = 0.96) indicating pleiotrophic effects of growth habit, causing epigonal and severely determinate types to be darker in leaf color/chlorophyll content (Noffsinger et al., 2006b). The range of values shown in Fig. 3 indicates that one could possibly select for higher chlorophyll content within growth habit types, if this were found to be tied to a useful trait such as water use efficiency, which has been found in corn and peanut.

Height to first mainstem pod was 5 to 107 cm and height to first basal mainstem pod was 2 to 120 cm in the F2:7 (data not shown). Some of this was growth habit related but, there was still considerable variation within growth habit types and even within some RILs, indicating opportunities for selection.

In Table 3, pod wall proportion was less for epigonal types (1), which should be expected given the early abortion of most unfilled pods. The low seed weight values indicate inheritance from Tifwhite-78.

REFERENCES

Noffsinger, S.L., H.L. Bhardwaj, and E. van Santen. 2006a. An ideotype for winter-type grain white lupin in the southeastern USA. p. 64-67. In E. van Santen and G.D. Hill (eds.) Proceedings of the 11th International Lupin Conference, Guadalajara, Jalisco, Mexico. May 4-5, 2005. International Lupin Association, Canterbury, New Zealand.

Noffsinger, S.L., H.L. Bhardwaj, and E. van Santen. 2006b. Cherish your exceptions: some unusual phenotypes in an F8 indeterminate x determinate RIL population. p. 72-79. In E. van Santen and G.D. Hill (eds.) Proceedings of the 11th International Lupin Conference, Guadalajara, Jalisco, Mexico. May 4-5, 2005. International Lupin Association, Canterbury, New Zealand.

Fig. 1. Agronomic trait variation in winter-type white lupin: (A) earlier and later mainstem flowering, (B) a severe epigonal type,

and (C) segregation for determinate vs. indeterminate growth in a F2:7 RIL.

(A) (B) (C)

Fig. 2. The full range of determinate through indeterminate growth habit

was displayed in the F2:7 and F8 RIL populations. The female parent,

Tifwhite-78, was a traditional indeterminate type (7-7.5), and the male parent, Lucyanne, was a traditional determinate type (4-4.5).

1 to 1.5 = Epigonal

2 to 2.5 =Semi-epigonal

3 to 3.5 =Epigonal determinate

4 to 4.5 =Determinate

5 to 5.5 =Semi-determinate

6 to 6.5 =Semi-indeterminate

7 to 7.5 =Indeterminate

8+ = Highly Indeterminate

Fig. 3. Growth habit type vs. SPAD meter readings for the mainstem of

208 F2:7 RILs, April 20, 2003. The mainstem was killed by the lupin fly

(Hylemia lupini L.) so basal mainstem growth developed at the same time as the mainstems and was treated as mainstems for the SPAD readings.

0

20

40

60

80

1 2 3 4 5 6 7 8

Growth habit type (scale 1-8)

SP

AD

met

er r

ead

ing

Table 1. Segregation for growth habit in 13 F2:7 RILs. RILs 1056, 1115, and 1142 had more subtle segregation in the 6-8 range for the F8, and would require further generation advance to verify growth habit segregation.

F2:7 RIL 1 to 1.5 2 to 2.5 3 to 3.5 4 to 4.5 5 to 5.5 6 to 6.5 7 to 7.5 8

1002 1 2 3

1006† 6

1011 2 3

1016 3 1

1085 1 4

1088 1 1

1095 1 1 1

1107† 6

1120 4 2

1143 1 4

1160 1 3

1188 1 5

1191 2 2

†These lines were segregating for mainstem leaf number in the F2:7 and segregated

(especially 1107) for growth habit in the F8.

Growth Habit Rating

Table 2. Chi-square ratios for the growth habit types of F2:7 RILs.

Ratios 1 2 3 4 5 6 7 8

9 29 19 14 16 18 74 35

Expected 3:1 87 127 P0.05 = 3.84 54 161

X 2 = 29 21 7

Expected 9:7 87 127 P0.05 = 3.84 94 120

X 2 = 0.9 0.5 0.4

Growth Habit Classes

-------------------------- Total Plant No ---------------------------

Growth Type

1 26.53 ± 4.22 17.77 ± 2.59 75.60 ± 32.031.5 36.79 ± 2.06 23.36 ± 1.26 96.52 ± 15.632 34.47 ± 1.47 22.92 ± 0.91 146.32 ± 11.18

2.5 33.41 ± 1.08 22.69 ± 0.66 98.18 ± 8.223 33.02 ± 1.22 24.33 ± 0.75 93.85 ± 9.25

3.5 28.42 ± 2.99 19.79 ± 1.83 179.20 ± 22.654 35.40 ± 1.53 22.87 ± 0.94 100.18 ± 11.62

4.5 32.10 ± 2.85 20.38 ± 1.75 100.64 ± 21.595 38.95 ± 1.97 22.98 ± 1.21 114.13 ± 14.93

5.5 39.53 ± 1.97 23.47 ± 1.21 130.17 ± 14.936 39.45 ± 1.55 22.23 ± 0.94 104.92 ± 11.62

6.5 37.72 ± 1.72 23.27 ± 1.06 107.53 ± 13.087 38.69 ± 0.68 24.85 ± 0.42 94.44 ± 5.17

7.5 36.14 ± 0.93 25.39 ± 0.57 86.99 ± 7.098 38.19 ± 0.81 24.78 ± 0.50 94.46 ± 6.12

Podwall % 100 Seed weight Seed no. plant-1