The Centrality of Seed: Building Agricultural Resilience Through Plant Breeding

Salvatore Ceccarelli

Unlike conventional farming methods, participatory plant breeding allows farmers to make their own decisions on which seeds to plant and thereby become part of the evolutionary process.

The five glob­al issues most fre­quent­ly debat­ed today are: the decline of bio­di­ver­si­ty (agro­bio­di­ver­si­ty in par­tic­u­lar), cli­mate change, hunger and mal­nu­tri­tion, pover­ty and water. Seed is cen­tral to all five issues. The way in which seed is pro­duced has been arguably their major cause. But it can also be their solution.

Dur­ing the mil­len­nia before mod­ern plant breed­ing began farm­ers were mov­ing around with seeds and live­stock, and because nei­ther were uni­form they could grad­u­al­ly adapt to dif­fer­ent cli­mates, soils and uses. When­ev­er farm­ers set­tled, they con­tin­ued to improve crops and live­stock. In the case of crops, the way they did it, which can still be seen today in a num­ber of coun­tries, con­sists of select­ing the best plants to pro­vide the seed to be used for the fol­low­ing sea­son. This process was high­ly loca­tion-spe­cif­ic in the sense that each farmer did it inde­pen­dent­ly from oth­er farm­ers and for his/​her con­di­tions of soil, cli­mate and uses. The enor­mous diver­si­ty of what we call ancient, old, heir­loom vari­eties orig­i­nat­ed through this process.

Prob­lems Cre­at­ed by Indus­tri­al Agriculture

The tran­si­tion to mod­ern plant breed­ing was accom­pa­nied by a change from selec­tion for spe­cif­ic adap­ta­tion to selec­tion for wide adap­ta­tion: this became the dom­i­nant breed­ing phi­los­o­phy and was the basic breed­ing prin­ci­ple adopt­ed by the Green Revolution.

The term Green Rev­o­lu­tion” is used to indi­cate an agri­cul­ture devel­op­ment strat­e­gy based on the use of new vari­eties, in con­junc­tion with the use of fer­til­iz­ers, pes­ti­cides, irri­ga­tion water and mech­a­niza­tion. It is now increas­ing­ly rec­og­nized that the short-term achieve­ments of the Green Rev­o­lu­tion had long-term penal­ties. One was the reduc­tion in food diver­si­ty with neg­a­tive con­se­quence on human health. Anoth­er was the leach­ing into the ground water of fer­til­iz­ers due to overuse, but they also includ­ed water short­ages, the emer­gence of pes­ti­cide resis­tance, the increase in pop­u­la­tions of harm­ful insects and the bypass­ing of farm­ers in mar­gin­al areas.

GMOs, the lat­est addi­tion to the indus­tri­al tool­box,” are a short-term and unsta­ble solu­tion to these prob­lems because they change the envi­ron­ment sur­round­ing the organ­isms they intend to con­trol. Thus, as pre­dict­ed by a fun­da­men­tal bio­log­i­cal prin­ci­ple, name­ly the Fun­da­men­tal The­o­rem of Nat­ur­al Selec­tion, their use induces resis­tance. It is the same process by which bac­te­ria evolve resis­tance to antibi­otics, a phe­nom­e­non that is the cause of dis­eases affect­ing year­ly two mil­lion Amer­i­cans and caus­ing 23,000 deaths in the Unit­ed States. At best, GMOs can only be a short-term solu­tion to any par­tic­u­lar prob­lem, but in every case they have cre­at­ed an often more seri­ous prob­lem (resis­tant weeds, insects or dis­ease) that requires a new GMO and/​or more chem­i­cal use. They also make a farmer com­plete­ly depen­dent on the com­pa­ny pro­duc­ing the GMOs and chemicals.

Agroe­col­o­gy and Alter­na­tive Meth­ods of Plant Breeding

Agroe­co­log­i­cal mod­els of agri­cul­ture, such as organ­ic agri­cul­ture, could be solu­tions to the most impor­tant prob­lems affect­ing the plan­et, but they are often crit­i­cized for not being able to pro­duce enough food for a grow­ing pop­u­la­tion. We believe, how­ev­er, that most of the meta-analy­sis show­ing low­er yields under organ­ic con­di­tions are biased by the use of vari­eties which were not select­ed specif­i­cal­ly for organ­ic conditions.

Par­tic­i­pa­to­ry and evo­lu­tion­ary plant breed­ing meth­ods rec­on­cile increased pro­duc­tion of more read­i­ly avail­able and acces­si­ble food with increased agro­bio­di­ver­si­ty. They also main­tain the evo­lu­tion­ary poten­tial of our crops, which is need­ed to cope with cli­mate change. Being based on selec­tion for spe­cif­ic adap­ta­tion, par­tic­i­pa­to­ry plant breed­ing is not only more effi­cient than con­ven­tion­al plant breed­ing, but is able to pro­duce vari­eties specif­i­cal­ly adapt­ed to both an agroe­co­log­i­cal agri­cul­tur­al mod­el and diverse local cli­mates. There­by food safe­ty is rec­on­ciled with food security.

Par­tic­i­pa­to­ry bar­ley breed­ing. (Pho­to: Inde­pen­dent Sci­ence News)

Par­tic­i­pa­to­ry Breed­ing of Toma­toes for Organ­ic Farming

An exam­ple that this is indeed pos­si­ble at low cost and in a short peri­od of time is the fol­low­ing three year project of par­tic­i­pa­to­ry toma­to breed­ing in organ­ic conditions.

In Italy, four sin­gle cross­es rep­re­sent­ing four dif­fer­ent toma­to types (name­ly cuore di bue”, long fruit”, cher­ry toma­to” and green sal­ad fruit”) were self fer­til­ized to pro­duce four F2 pop­u­la­tions. These F2 seeds were dis­trib­uted to four organ­ic farm­ers locat­ed along a 450 km tran­sect of the Ital­ian Adri­at­ic coast.

Each farmer grew a ran­dom sam­ple of 72 indi­vid­ual F2 plants for each of the four cross­es, togeth­er with 18 indi­vid­ual plants of a com­mer­cial F1 hybrid of the cor­re­spond­ing fruit type for a total of 360 plants (4 cross­es x 90 plants). The four pop­u­la­tions were also plant­ed at the research station.

In the farm­ers’ fields, a group of farm­ers and a group of sci­en­tists con­duct­ed inde­pen­dent­ly a visu­al selec­tion on indi­vid­ual plants express­ing their opin­ion with a 1 (worse) to 4 (best) score. At the research sta­tion, only sci­en­tists con­duct­ed the selection.

After sta­tis­ti­cal analy­sis, seed was extract­ed from the fruits of the best plants and the cor­re­spond­ing F3 fam­i­lies (8 plants per fam­i­ly) were grown togeth­er with the same com­mer­cial hybrid as in the first year. Dur­ing the process the F3 seed of the select­ed F2 of the green sal­ad” pop­u­la­tion was lost because of poor seed germination.

Selec­tion was repeat­ed with the same method­ol­o­gy and the best plants were used to obtain the seed of the F4 fam­i­lies of the three remain­ing cross­es. These were com­pared with com­mer­cial hybrids in a repli­cat­ed (3 repli­ca­tions) tri­al on the four farms and at the research sta­tion. The tri­als on farms had some lines in com­mon (select­ed in more than one farm) but also the unique selec­tions on that farm.

To assess yield, we mea­sured the pro­duc­tion of the first three fruit clus­ters. These are both very vul­ner­a­ble to late frosts and very valu­able to the farm­ers for the high prices of an ear­ly sea­son toma­to. It is thus a key com­mer­cial trait for farmers.

The result of the three years par­tic­i­pa­to­ry selec­tion were iden­ti­fi­ca­tion of three fam­i­lies which out-yield­ed sig­nif­i­cant­ly the respec­tive com­mer­cial hybrid and anoth­er 12 fam­i­lies which yield­ed as much as the com­mer­cial hybrids. All the three fam­i­lies which sig­nif­i­cant­ly out yield­ed the respec­tive com­mer­cial hybrid were select­ed from the same pop­u­la­tion (the long fruit” type). Two of these fam­i­lies had a yield advan­tage over the com­mer­cial hybrid of between 43 and 44 per­cent. The third fam­i­ly out-yield­ed the com­mer­cial hybrid in two of the four farms by 62 and 76 per­cent, but it was sig­nif­i­cant­ly low­er yield­ing (-22 per­cent) than the same hybrid on the research sta­tion. Had we con­duct­ed the breed­ing pro­gram only at the research sta­tion, we would have missed such a line.

Part of the eval­u­a­tion was a score for uni­for­mi­ty and none of these lines was phe­no­typ­i­cal­ly less uni­form than the hybrid. This means that they can be imme­di­ate­ly com­mer­cial­ized, thus cap­i­tal­iz­ing on the work done. The lines still con­serve some genet­ic diver­si­ty, which allows farm­ers to con­tin­ue to improve them by extract­ing seeds from the best fruits of the best plants. The three advan­tages farm­ers derived from this work are 1) high­er yield­ing vari­eties; 2) sav­ing on pur­chased seed as they can pro­duce their own, and 3) using vari­eties specif­i­cal­ly adapt­ed to organ­ic conditions.

Beyond par­tic­i­pa­to­ry plant breeding

There are sev­er­al oth­er exam­ples of suc­cess­ful par­tic­i­pa­to­ry breed­ing pro­grams, but despite these suc­cess­es par­tic­i­pa­to­ry plant breed­ing has a weak­ness in requir­ing the col­lab­o­ra­tion of a research insti­tute to pro­vide breed­ing mate­r­i­al and tech­ni­cal sup­port such as exper­i­men­tal design and sta­tis­ti­cal analy­sis. There­fore, the sus­tain­abil­i­ty of a par­tic­i­pa­to­ry pro­gram depends on the long-term com­mit­ment of a research institution.

An inter­est­ing alter­na­tive is offered by evo­lu­tion­ary (par­tic­i­pa­to­ry) plant breed­ing — par­tic­i­pa­to­ry is in paren­the­sis because, though desir­able, the par­tic­i­pa­tion of an Insti­tu­tion is not indis­pens­able. The idea is not new as it was pro­posed by Colt A. Sune­son in 1956. The method con­sists in plant­i­ng in farm­ers’ fields with mix­tures (evo­lu­tion­ary pop­u­la­tions) of very many dif­fer­ent geno­types of the same crop, prefer­ably, but not nec­es­sar­i­ly, using ear­ly seg­re­gat­ing gen­er­a­tions. These pop­u­la­tions will be plant­ed and har­vest­ed year after year, and due to nat­ur­al cross­ing (high­er in cross-pol­li­nat­ed and less in self-pol­li­nat­ed crops), the genet­ic com­po­si­tion of the seed that is har­vest­ed is nev­er the same as the genet­ic com­po­si­tion of the seed that was plant­ed. In oth­er words, the pop­u­la­tion evolves to become pro­gres­sive­ly bet­ter adapt­ed to the envi­ron­ment (soil type, soil fer­til­i­ty, agro­nom­ic prac­tices includ­ing organ­ic sys­tems, rain­fall, tem­per­a­ture, etc.) in which it is grown. As the cli­mat­ic con­di­tions vary from one year to the next, the genet­ic make­up of the pop­u­la­tion will fluc­tu­ate, but if the ten­den­cy is towards hot­ter and dri­er cli­mat­ic con­di­tions, as expect­ed in view of cli­mate change, the geno­types bet­ter adapt­ed to those con­di­tions will grad­u­al­ly become more fre­quent in this farming/​breeding system.

Farm­ers breed­ing toma­toes in the field. (Pho­to: Inde­pen­dent Sci­ence News)

The evo­lu­tion­ary pop­u­la­tion, which can be made by the farm­ers them­selves by buy­ing seed of as many dif­fer­ent vari­eties (includ­ing hybrids) of a giv­en crop, can be used by the farm­ers (and by researchers if they are will­ing to par­tic­i­pate) as a source of genet­ic diver­si­ty from which to select plants with use­ful traits.

This has been done in Italy using a zuc­chi­ni (sum­mer squash) evo­lu­tion­ary pop­u­la­tion obtained by let­ting 11 com­mer­cial hybrids to freely inter­cross. After only two cycles of visu­al selec­tion, as in the case of toma­to, the farmer in ques­tion select­ed two vari­eties, dif­fer­ing in col­or, yield­ing as much as the com­mer­cial hybrids. He has already start­ed sell­ing the two new vari­eties in local markets.

Thus evo­lu­tion­ary (par­tic­i­pa­to­ry) plant breed­ing, being a rel­a­tive­ly inex­pen­sive and high­ly dynam­ic strat­e­gy to adapt crops to a num­ber of com­bi­na­tions of both abi­ot­ic and biot­ic stress­es and to organ­ic agri­cul­ture, seems to be a suit­able method to gen­er­ate, direct­ly in farm­ers’ hands, the vari­eties that will feed the cur­rent and future pop­u­la­tions. Com­bin­ing seed sav­ing with evo­lu­tion and return­ing con­trol of seed pro­duc­tion to the hands of farm­ers, it can pro­duce bet­ter and more diver­si­fied vari­eties. These can help mil­lions of farm­ers to reduce their depen­dence on exter­nal inputs and their vul­ner­a­bil­i­ty to dis­ease, insects and cli­mate change and ulti­mate­ly con­tribute to food secu­ri­ty and food safe­ty for all.

(A ver­sion of this arti­cle appeared on inde​pen​dentscience​news​.org.)

For­mer­ly a pro­fes­sor in agri­cul­tur­al genet­ics at the Uni­ver­si­ty of Peru­gia, Italy, Sal­va­tore Cec­ca­rel­li has been asso­ci­at­ed with the Inter­na­tion­al Cen­ter for Agri­cul­tur­al Research in the Dry Areas (ICAR­DA) since 1980.
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