The Free Sterol Content of Selected Clones of Alfalfa As Related to Seed Infestation by the Alfalfa Seed Chalcid
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Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 5-1967 The Free Sterol Content of Selected Clones of Alfalfa as Related to Seed Infestation by the Alfalfa Seed Chalcid Rex Alton Richards Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Plant Sciences Commons Recommended Citation Richards, Rex Alton, "The Free Sterol Content of Selected Clones of Alfalfa as Related to Seed Infestation by the Alfalfa Seed Chalcid" (1967). All Graduate Theses and Dissertations. 2974. https://digitalcommons.usu.edu/etd/2974 This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. THE FREE STEROL CONTENT OF SELECTED CLONES OF ALFALFA AS RELATED TO SEED INFESTATION BY THE ALFALFA SEED CHALCID by Rex Alton Ri chards A thesis submitted in partial fulfillment of the requirements f or the degree of MASTER OF SCIENCE in Plant Nutrition and Biochemistry UTAH STATE UNIVERSITY Logan , Utah 1967 ACKNOWLEDGMENTS I would like t o express my sincere appreciation t o my major professor, Dr . Keith R. Allred , and to Dr. Herman H. Wiebe and Dr. Orson S. Cannon of my thesis committee for their assistance and direction in this study. wish to acknowledge my parents, Mr . and Mrs. Alton F. Richards, for their aid and encouragement. Also, I wish to acknowledge the financial support given me through the William C. Claypool Fellowship in Agriculture and Basic Re search Project 660 of the Agricultural Experiment Station. TABLE OF CONTENTS Page INTRODUCTION 1 REVIEW OF LITERATURE 3 Alfalfa Seed Chalcid 3 Class~fication of tnsec c 3 Growth and developme nt 4 Emergence 4 Oviposition 4 Life cycle . 5 Generat ons per year 5 Distribution 6 Description of t he damage 6 Economic impoi tance 7 Control . 8 Cu ltural 8 Natural 8 Chemical 9 Resistance 9 Sterols 10 Occurrence i n plants 11 Uses of sterols 11 Chern stry 12 Steroids 12 Sterols 13 Cholesterol biosynthesis 13 Methods fo r the determinatton of plant sterols 14 METHODS OF PROCEDURE 16 Establishing Fteld Plots 16 Harvesti ng and Preparing Plant Samples 18 Leaves and stems 18 Ra cemes , 18 Dark-green pods . 18 TABLE OF CONTENTS (cont1nued) Page Mature tagged pods 19 Mature un- tagged pods 20 Determination of Free Sterol Content 20 Chem~ca l procedure 20 Work ng urve 23 Determination of Percent Alfal fa Seed Chalcid Infes tatlon 24 Statistical Analysl s 24 RESULTS AND DISCUSSION 25 Free Sterol Content 25 Stems 25 Leaves 28 Flowers 28 Pods 29 Summary of the free sterol ontent data 29 Percent Chalcid Infestat on 32 Mature non-tagged pods 32 Mature tagged pods 34 Percent c halcld i nfes tati on of four years 35 Weev i l I nfestation 36 Relatlonships Among Variables 38 Ste rol content ver s us percent c halcid 1. nfesration 38 Sterol conte nt ver sus weevil i nfestation 38 Tagged infestation versus un-tagged i nfestation 40 SUMMARY AND CONCLUSIONS 42 LITERATURE CITED 45 APPENDIX 50 VITA 52 LIST OF TABLES Table Page 1. Names and derivations of 12 clones of alfalfa used in alfalfa seed chalcid resistance studies 17 2 . Ranked means of the free sterol content in the stems, leaves, flowers, and pods of 12 clones of alfalfa 26 3. Sterol data that have been transl o rmed t o ~ how the percent of difference among Lhe lL ciones of alfalfa for each of the four plant parts . 30 4. Sterol rankings in the flowers, pods, stems and leaves 30 5. Summary of t he sterol content of the four plant parts 32 6. Ranked means of the per cent chalcid i nfestation (non-tagged seed) 33 7. Ranked means of the percent chalci d infestation (tagged seed) 34 8. Summary of percent chalcid infestation data for 1960, 1961, 1965 and 1966 (non-tagged seed) 36 9. Ranked means of the numbers of weevi l per 20 stems 37 10 . Correlation coefficients of all simple two-way comparisons between the sterol content of plant parts, percent chalcid infestation and weevil infestation 39 LIST OF FI GURES Figure Page 1. Exampl e of work~ng curve 51 The Free Sterol Content of Selected Clones of Alfalfa as Related o Seed Infestation by the Alfalfa Seed Chalcid Re~ Al on Richards , Master of Sc ience Utah State University, 1967 Major Professor : Dr . Ke1th R. Allred Department: Plant Science The infestation of twelve selected clones of alfalfa by the alfalfa seed chalcid was measured. The free sterol content of the stems, leaves, f lowers and pods of these clones was determined. A check was made to see if there was a correlation between the sterol content and the chalc1d infesta t1on. Differences were found among t he clones in the sterol content for each plant part . There were also signtficanr d1fferences in percent chalcid i nfestation in the 12 cl ones. Duncan ' s New Multiple Range Test pointed out whic h clones differed Slgnificantly from the others. Using linear regression analys1s, the correlation coefficient of the comparison between the sterol content and the chalc1d infestation was obtained . There was a signtflcant negat~v e corr e lation between the sterol content of the flower and the percent chalcid infestation. No sig- nificant correlation was found between t he sterol content of the stems, leaves or pods and the percent chal c td infestation. (59 pages) iNTRODUCTiON The alfalfa seed chalCI. d, Bruchophagus roddi (G uss.), is a small , black i nsect which resemb les a wasp . This tnsec t has been known t o be a pest t o the raising of alfalfa seed s nee the latter part of the ni neteenth century . Infest atton of the seed has been known to have run as high as 85 percent 1n some areas. Each year, thousands of acres of alfalfa s eed are destroyed and t housands of dollars are los t because of the l ack of alfalfa seed chalcid control. Utah loses 5 to 25 percent of i t s alfa l f a seed c rop yearly as a result of chalcid damage (Sorenson, 1930). Alfalfa s eed damage produced by the seed chalcid is not a localized problem. Wherever alfalfa is grown for seed, the yields have been reduced by th1s pes t . Several methods have been used to try to control the damage caused by t he alfalfa seed chalcid . Chemical s prays were tested but they had to be a bandoned because they tended to elimi nate all the insects of the order Hymenoptera. Th ts o rder contains not only the alfalfa seed chaloid, but also the bees and wasps. The bees are necessary for pollination and t hus are essential fo r seed production. This makes the use of sprays undes irable for the control of the chalcid. Another method that coul d be utiltzed to i ncrease seed yields 1s t he use or alfalfa vartetleo that a re less s u6 ceptible to infes- cation by t he insect Seve ra l <esearchers ha ve shown that there were 2 sign1f1cant differences 1n chalcid infestation among several alfalfa strains and varieties that were comp ared (M i nion, 1961; Rowley , 1962; and Strong, 1962a) . Certain chem1cal s found i n alf alfa have been s hown by Kamm and Fronk (1964) to have attractant or repellent properties to the alfalfa s eed chalcid. The quantity of these chem1cals in the plant may affec t the susceptibil ity o the plant t o i nsect 1nfestati on. The s terols were shown to be good chalc1d attractants by Kamm a nd Fronk i n t he research ment oned. The purpose of this study was to investigate the possible relation s hips between t he free sterol content of selected clones of alfalfa and the seed 1nfestation by the alfalfa seed chalcid . The objectives of this study were as follows : (1) Detenm ne the free s t erol content of the stems , leaves, flowers and pods of alfalfa clones which have been previously rated with regard to c halcld infestat ion , (2) De t e r mine the chalcid i nfestation of the selected cl ones for the season in which the plant material was collected , and (3) Check to see if there is a correlation between free sterol content a nd chalcid i nfes t a t ion. REVI EW OF LITERATURE Al f alfa Seed Chalc id Class ification of nsec t The alfalfa seed chalcid, a s mall Jet-black was p, has for years been referred t o as the clover s eed c halcid Bruchophagus gibbus (Boheman) . Re cent morpho ogtcal s tudtes have shown that what has been called the clover seed c halcid , .!l.· gtbbus i s actually three distinct species , .!l. · roddi, .!l.· gtbbus, and .!l.· kolobovae {Kolobova, 1950; Nikolskaya, 1952; Fedoseeva, 1954 ; Strong, 1962a). Strong (1962a) reported that separatton i s posstble on the basis of the female genitalia. First description of the chalctd in the United States came i n 1897 by Howard who considered tt a parasite of the seed mi dge, and named it Eu r ytoma f unebris. Ashmead changed the name to Bruchophagus f unebris believing that the chalcid parasitized the pea and bean seed weevtl s (Bruc hidae) . Urbahns (1920) reported that in 1891 Dr. Hopkins, after careful observations , found t hat t he chalc id was a pest of the lover seed.