Paper presented at the 5th International Lupin Conference, Poznań, Poland, July 5-8, 1988.Seed of 61 introduced genotypes of Lupinus mutabilis was screened for nitrogen, methionine and oil. There was marked variation among the characteristics in the genotypes screened. This suggests the possibility of selecting for increased levels of all three factors. There was a significant positive (P < 0.001) relationship between seed nitrogen and methionine

Bala, A.

Hill, G. D.

Savage, G. P.

Lincoln University Research Archive

B-1~ VARIATION IN OIL, NITROGEN AND METHIONINE LEVEL IN LUI'lNUS MUl"ABlLlS G.P. Savage l , G.D. HiIl*2 and A. Bala 2 Departments of BiochemistrJI and Plant Science2, Lincoln College, Canterbury, New Zealand. ABSTRACT Seed of 61 i ntrodllced genotypes of Lllpil1l1s 1711lfobifis was screened for nitrogen. meth ion ine and oil. There was marked variation among the characteristics in the genotypes screened. This suggestes the possibility of selecting for increased levels of all three factors. There was a significant positive ( P < 0.00 I) relationship between seed nitrogen and methionine. INTRODUCTION The species L.17J//wbilis has the highest seed oil concentration of any cultiva.ted lupin. Similarly. it has a high seed protein concentration l . It h<ls been suggested tl1(lt L.l11l1lobilis h<ls consider<lhle potential in South America as a crop for the Andes region 2-4 . Experiments have alrea9Y been conducted to evaluate its potential as a protein source in human diets5-l~. In com1110n with most legumes seed protein is low in methionine l . Sava~e C/ 01.1.3 showed that the nutritive value of cooked and leached L.l11l1lobilis could be considerably improved by adding up to 0.5% DL-methionine. With the same samples of cooked and leached seed it was further shown that the maximuill response to methionine was obtained with the addition of as little as 0.22 % 14. This suggests that selection of LlIll/lObilis with even marginally higher levels of methionine would have a considerable beneficial effect on the protein quality of cooked seed . In fact its biological value. at 84%. approaches that of unsupplemented. heat processed soya bean meal which is the major source of vegetable protein used in animal feeding. Seed oil is important both for its energy valut; in food. and because it~ financial value can help cover the cost of alkaloid extraction. To determine the variation in these major seed components. and their relationship with each other. the seed of 61 introduced genotypes of L.l11l1tabilis were screened for their oil. nitrogen and methionine content. MATERIALS AND METHODS The 61 genotypes were obtained by plant introductior from a variety of sources. All genotypes 'Nere grown together at Li ncol n College (a temperate em'i ron ment) during the 1980-1 growing season. under conditions of moderate fertility in an 8 x 8 simple lattice design. After harvest at the end of the growing season. oi I. nitrogen and meth ion ine were measu red on grou lid samples of whole seed. 577 Oil was determined on I g of ground sample by Soxhlct extraction in petroleum ether for 8 hours. Nitrogen was determined in triplicate by micro-Kjeldahl digestion with concentrated H 2S04 using K 2S04 /CuS0 4 (19 : I w/w) catalyst. The ammonium sulphate formed was analysed by an automated procedure lIsing a Technicon auto-analyser 15 . Methionine was measured using an automated method following pronase hydrolysis of ground seeplfi. RESULTS Oil: The mean oil concentration among the 61 genotypes was 14.74%. Values ranged from 11.65% in line 4176a to 17 .29% in H.T-I an introduction frol11 Peru. The majority of genotypes contained about 14.8% oil when grown in the Canterbury environment (FIG. I) 20 ~---------------------------------------------------------------, 1.5 5 --.--------.---1.1_~ 13.6 14.6 16.6 " orL 16.6 1. ?~ FIG. I. The distribution of oil concentration among 61 genotypes of L.lll11wvilis. Nitrogen: There was a similar wide range in nitrogen values among the 61 genotypes (Mean 7.44%: range 3.61-9.63%). The lowest value was in line 8076 and the highest in line 882 (FIG. 2). The median value was 7.69%. Methionine: There was nearly a fourfold variation in methionine concentration in seed protein. Values ranged from 210 mg/l6 g N (H6-77) to 1140 mg/16 g N (line 8376) with a median value of 470 mg/l6 g N (FIG. 3). 578 50 ~----------------------------------------------------------~ o FIG 2 . 20 1.5 ~ e ~ 10 I 5 o FIG. J. 3.5 4.6 5.6 e.~ 7.~ '" NITROGEN e.5 The distributi.on of nitrogen concentration among 6\ genotypes of L./1ll/labili~ . -_. __ . • 250 550 4(50 (550 650 '760 650 950 10501160 METHIONINE :ana/1e « N The distribution of methionine concentration among 61 genotypes of L.IIl/llobi/is. 579 ... Relationship lJetween Oil and Seed Nitrogen: There was no relationshi~ between the amount of oil al)d protein in the seed of the 61 genotypes of L.111111avili,1 tested (I' = 0.238. N.S.). The regression 3 rrf'lIl"'ted for only 5.75% of the total vari<lnce. Relationship IJetween Nitrogen and Methionine Concentration: The relatiol1<;hip between protein and methionine was sigllific~nt (P < 0 ,001) . The correlation coefficient (r) W<lS 0 ,524 and the fi'tting of the regression accounted for 27.5:1c of the variance . The regression equation was: Y 156.2 + 8RX Where Y is methionine in mgl16 g N. and X is (7, nitrogen in set"d (rIG, 4) , aoo 600 '$" ~ -~ 400 -.~ ;;§ ~ =- 200 o L-____ ~ ____ ~ ____ ~ ______ ~ __________ ~ ____ ~ ______ ~ ____ _ 3 a "7 e 9 10 " Nitro a_:r1 FIG. 4. The relationship between seed nitrogen concentration and methionine (mg/16 g N) in 61 L.Mlllavi/is genotypes. DISCUSSION The wide variation ill oi I. nitrogen and methion i ne concentration observed among these 61 genotypes of L.mll/obi/is suggests that it should be possible to select genotypes of this important South American lupin species for increased seed oil concentration. increased nitrogen content. <lnd improved protein quality, 580 . It is eVident that the level of oil and nitrogen in Lll7lflobili.1 can be innuenced hy climate. When 17 of the genotype~ grown here were grown in Canterburv in 1978. in a season that was considt'rably warmer than "sual. the mean seed nitrogen concentration was 6.98% (range 6.41-7.54%). Oil values on the other hand were considerably hi!!her (mean. 18.067<: range 15.7"-22.03%)17. However. contary to the report of Horn ('I 01.17 see<:1 oil. in L.11111lobilis in this experiment. was not directly related to seed nitrogen concentration. Selection for one would therefore not 'ecessarily produce a reduction in the concentration of the other. The positive relations h ip benveen seed nitrogen concentration and meth ion i ne I. !his species (FIG. 4) suggests that selection of genotypes with a high seed nitrogen would also increase seed methionine level. It also suggests that the major storage proteins in L.l11l1labilis are high in methionine. Whether this is the case or not. will depend on further biochemical analysis of the seed globuli ns of L.1Il11 /Obi lis. REFERENCES 1. Hill. G.D. Nlllr.Abslr.Rc'·'.n. 1977. 47. 511. 2. Gross. R.: Baer. E. von Z.Ernohnfl1gslI'iss. 1975. /4.224. 3. Ortiz. c.: Gross. R.: Baer. E. von Z.FmohrungslI'is.l. 1975. /4.230. 4. Gross. R.: Baer. E. \,on Arch.LOlillolllcr.Nlllr. 1977.27.451. 5. Reyes . .T.: Gross. U.: Ponce. L.: Serp::l. l..,1. I'roc.lnl.Lllpill COllI 1980. /.708 6. Reyes . .T.: Gross. U. rroc./Il/.Lupin COI!t:. 1982.2.331. 7. Reynoso. Z.: Nella. S.: Gross. U.: Gross. R. J'roC.JIlI.LlIpil1 Cant: 1982. 2.346. 8. ROl1lana. G.L: de: Graham. G.G.: Morales. E.: Massa. E.: MacLean. W.e. /'roc.lIl/.Lllpil1 Cal!/: 1982. 2. 355. 9. Gross. U.: Galindo. R.G.: Schoeneberger. M. Quol./'/all/. 1983. 32. 155. 10. Romana. G.L. de: Graham. G.G.: Morale~. E.: Massa. E.: MacLean. W.e. i.Nulr. 1983. / 13. 773. II. Reyna . .1.: Wittung. W. "roc./IlI.Lllpin COI!t: 1984. 3. 649. 12. Romana. G.L. de I'roc./nl.Lllpill COI!( 1984.3.45.1. 13. Savage. G.P.: Allington. E.H.: Hill. G.D. l'roc.lnl.l.lIpil1 COl~r 1982. 2.295 14. Savage. G.P.: Young . .T.M.: Hill. G.D. /'roc./nl.Lupil1 COIlt: 1984.3.629. 15. Mann. L:f . .T. Anol.Chcl11. 1963.35.2179. 16 Ussary. J.P.: Gehrke. C.W. /'roc.Tcc/7nic./I1I.COII.r.:. 1969.89. 17. Horn. P.E.: Hill. G.D.: Porter. N.G. "roc.Agl'On.Sot'.N.Z. 1978. 8.73. 581 " 

Variation in oil, nitrogen and methionine level in Lupinus mutabilis

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