Alcantara, P. B.

Tsuhako, A. T.

Usberti, J. A., Jr.

Usberti, R.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XXI International Grassland Congress / VIII International Rangeland Congress Effects of Selection for Seed Size on Grazing‐Type Population of an Inter‐Specific Hybrid (Pennisetum purpureum × P. glaucum) R. Usberti Plant Protection Agency, Brazil J. A. Usberti Jr. Campinas Agronomic Institute, Brazil P. B. Alcantara Zootecnia Institute, Brazil A. T. Tsuhako Matsuda Seed and Animal Nutrition Co., Brazil Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/21/14-1/13 The XXI International Grassland Congress / VIII International Rangeland Congress took place in Hohhot, China from June 29 through July 5, 2008. Proceedings edited by Organizing Committee of 2008 IGC/IRC Conference Published by Guangdong People's Publishing House This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. 　 Multifunctional Grasslands in a Changing World 　 Volume Ⅱ 　 瞯 ]561　 瞯Grasslands/Rangelands Production Systems——— Seed Science and TechnologyEffects of selection for seed size on grazing‐type population of an inter‐specific hybrid( Pennisetum purpureum × P . glaucum)R . Usberti1 , J . A . Usberti Jr .2 , P . B . A lcantara3 and A . T . Tsuhako41 Plant Protection A gency , Camp inas , E‐mail : usberti ＠ cati .sp .gov .br 2 A gronomic Institute , Camp inas ; 3 ZootechnicInstitute , Nov a Odessa ; 4 Matsuda Seeds and A nimal Nutrition Co . , A lv ares Machado , Braz il .Key words : Pennisetum purpureum × P . glaucum ,seed size selection ,grazing‐type populationIntroduction The original inter‐specific hybrid Pennisetum purpureum × P . glaucum was a cross‐pollinated population quite variable asto morpho‐agronomic , forage and seed traits ( Schank et al . ,１９９６) . Recurrent selection was able to significantly increase seed physicalpurity and phenotypical uniformity of resulting populations‐cutting and grazing types ( Usberti et al . ,２００５) . However , little is knownabout the behavior of seed size during the selection process , which might be very useful for the development of new cultivars , and it isthe main purpose of this research work .Materials and methods A grazing‐type population was scored as to its seed size frequencies ( SSF) , during the ２００６ growing season .Seed samples were picked up , seed physical purities ( SPP) and numbers of intact seeds/ gram ( NIS) scored for all individual plants .Separation of large , intermediate or small seed size was carried out , based on mean standard deviations‐MSD ( large and small seedsidentified whenever NIS , in the sample , was one MSD below or above the average , respectively and intermediate size ones in theinterval) . The original population was split into two sub‐populations ( P‐８ and P‐M ) , each one carrying large and small seed‐sizedprogenies , which were sown in isolated plots . In the ２００７ growing season seed samples were again picked up from all individual plantsof the selected sub‐populations and scored for SSP , NIS and numbers of chemically scarified ( treatment with H２ SO４ ,１０�) seeds/ gram(NSS) ; seed size frequencies ( SSF) were also determined . Finally , linear correlations between the cited seed traits were estimated .Results and discussion Selection for seed size caused significant changes on SSF of the resulting sub‐populations . Intermediate SSFincreased in all cases , mostly at the expense of a remarkable reduction of large SSF , small SSF remaining constant ( Table １) . Clearly ,there might be some sort of stabilizing selection in action , which favors the occurrence of medium‐sized seeds . Estimated linearcorrelations between SPP and NIS , NSS ( Table ２ ) have shown high and negative values as well as high and positive NIS × NSScorrelations , for most of the selected sub‐populations . So , there is a strong trend that the higher the NIS or NSS ( small seeds) , thesmaller the SPP , and vice versa for large seeds . It suggests that an individual plant has a limited amount of energy allocated toreproductive activities , which becomes unable to produce whole seeds whenever occurs a higher amount of them ( high production ofempty seeds) . Finally , the evolution of SPP , NIS and NSS after two selection cycle ( Table ３ ) seems to be based on an overallreduction of seed size ( significant increases in NIS and NSS in all cases , but much more pronounced on the last ones) . On the otherhand , mild decreases in SPP were observed in large seed sub‐populations (１９ .４％ , on the average) but severe ones in small seed sub‐populations (４７ .４％ , on the average) . The same principle of energy allocation might explain these results .Table 1 Seed size f requency distributionsobserved on the original and desired graz ing‐type Purpureum x P . glaucum populations .PopulationOriginalGrazingTypeGrowing Season ２００６ 抖Intact Seed Size Frequency ( ％ )Large Intermediate Small３９ W.４ ４８ 後.８ １１ ?.８Growing Season ２００７ 抖Seed Size Frequency ( ％ )Intact Seeds Scarified SeedsP８‐LS ８ +.３ ７９ 殚.２ １２ 槝.５ ８ 9.３ ８３ 鲻.８ ８ 棗.３P８‐SS ５ +.９ ７７ 殚.７ １６ 槝.４ １２ G.９ ６９ 鲻.５ １７ Ζ.６PM‐LS ２０ 9.４ ６８ 殚.７ １１ 槝.３ １１ G.３ ７５ 鲻.０ １３ Ζ.７PM‐SS １２ 9.６ ７１ 殚.０ １６ 槝.４ １７ G.７ ７１ 鲻.０ １１ Ζ.３Observations :P８ and PM ＝ Selected populations ;LS ＝Large seed ;SS ＝ Small seedTable 2 Estimated linear correlationsbetween seed physical purity (SPP) andnumber o f intact and scari f ied seeds / g(NIS/ g and NSS/ g) observe in selectedgraz ing‐type populations o f Pennisetumpurpureum × P . glaucum .Population SPP ×NIS/g SPP ×NSS/ g NIS/ g ×NSS/ gP８‐LS ‐０ 篌.５４ ‐０ �.５７ ０ 2.６９P８‐SS ‐０ 篌.５４ ‐０ �.６４ ０ 2.５７PM‐LS ‐０ 篌.７４ ‐０ �.６４ ０ @.６PM‐SS ‐０ 篌.２３ ‐０ �.０４ ０ 2.３０Observations :P８ and PM ＝ Selected grazing‐typepopulations ;LS ＝ Large seed ;SS ＝ Small seedTable 3 Seed physical purity( SPP) and number o f intact and scari f iedseeds / gram (NIS/ g and NSS/ g) recorded on four selected populationso f graz ing‐type hybrids o f Pennisetum purpureum × P . glaucum in twoconsecutive growing seasons (２００６ and ２００７ )PopulationGrowing Season２００６  ２００７ wSPP NIS/ g NSS/ g SPP NIS/ g NSS/ gOriginal P８ �６８ 贩.９ ３２３ 殚.１ ４４９  .４ ‐ ‐ ‐P８‐LS ６７ 贩.２ ２２６ 殚.４ ３７７  .６ ５７ #.８ ３０８ V.５ ４５３ p.８P８‐SS ６４ 贩.２ ３７４ 殚.４ ５３５  .５ ３３ #.８ ４６１ V.６ ７４８ p.１Original PM ６６ 贩.１ ３２２ 殚.２ ４７９  .４ ‐ ‐ ‐PM‐LS ６６ 贩.６ ３０７ 殚.７ ３６８  .５ ５０ #.０ ３３８ V.０ ５５６ p.７PM‐SS ６１ 贩.９ ３４３ 殚.３ ６１９  .２ ３２ #.６ ４５０ V.６ １０４１ �.５Observations :P８ and PM ＝ Selected grazing‐type populations ;LS ＝ Large seed ;SS ＝Small seedConclusions Selection for seed size significantly affects its frequencies of the resulting populations , with predominance of medium‐sizeseeds . It has also been observed a marked trend of seed size reduction during the selection process ( significant increases of numbers ofintact and scarified seeds) along with drastic reduction of seed physical purities in small seed size populations . It can be suggested , insimilar selection schemes , the choice of genetic materials with medium‐size seeds , to avoid undesirable fluctuations in expected seedproductions .ReferencesSchank SC , Diz DA , Hogue PJ and Vann C . (１９９６) . Evaluation of pearl millet x elephantgrass hybrids for use as high quality foragefor livestock . Soil and Crop Science Society o f Florida Proceedings , ５５ , １２０‐１２１ .Usberti R , Usberti Jr JA , Aguiar RH , Carneiro LMTA , Fantinatti JB , Francisco FG . ( ２００５ ) . Effects of a recurrent selectionscheme , applied to an interspecific hybrid Pennisetum purpureum Schum . ( elephantgrass) × Pennisetum glaucum ( L .) R . Br .Stuntz ( pearl millet) , on several seed quality parameters . XX International Grassland Congress Proceedings , １ , ６２ .

Effects of Selection for Seed Size on Grazing‐Type Population of an Inter‐Specific Hybrid (\u3ci\u3ePennisetum purpureum\u3c/i\u3e × \u3ci\u3eP. glaucum\u3c/i\u3e)

https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=3444&amp;context=igc

Effects of Selection for Seed Size on Grazing‐Type Population of an Inter‐Specific Hybrid (\u3ci\u3ePennisetum purpureum\u3c/i\u3e × \u3ci\u3eP. glaucum\u3c/i\u3e)

Abstract

Similar works

Full text

Available Versions

University of Kentucky