BULLETIN - Heliconia Society International

PAGE 8 THE BULLETIN // JANUARY 2005 2010sizes but commonly weigh around 200 grams. Inside thereis only edible pulp with the remnants of seeds (present asbrown specks in the pulp). Seeds are rarely, if ever foundin the pulp. Even if the female flowers are pollinated, theproduction of seeds is very low and some cultivars arecompletely sterile and never form seeds (Simmonds, 1960;Champion, 1967). There are some cultivars that will set afew seeds if pollinated but the seed production is very low.More than 10 seeds per fruit are unusual with the averagenumber being much lower (Simmonds, 1960). The cultivarsthat have retained a small degree of female viabilityare very important in banana breeding programs aroundthe world. The use of these cultivars in improving the ediblebanana is described below (Champion, 1967; Fawcett,1913; Kervégant, 1935; Jacob, 1952; Valmayor et al.,2002; Shanmugavelu et al., 1992; Bakry, et al., 2009).Bananas are an important food crop and rank fourthworldwide behind rice, wheat, and corn. Less than 15% ofthe bananas produced around the world enter the exportmarket. The remainder of the fruit are consumed locally.The members of the Cavendish group are the most commonlygrown bananas for export purposes (Bakry et al.,2009). In the United States the average person consumesaround 25 pounds of bananas per year, but in some parts ofAfrica the average consumption approaches 550 poundsper year (Bioversity International, 2000). In addition tobeing consumed in the ripe state, bananas are also used inthe green cooked stage, to brew beer and in a variety ofother foods (Bakry et al., 2009; Bioversity International,2000; Karamura, 1998).The Problem with DiseasesBanana pests and pathogens that cause diseaseshave co-evolved with their host plants within the purportedcentres of origin where the greatest diversity exists today.The wild seeded banana species typically possess resistanceto a variety of diseases that attack banana plants beinggrown for fruit production. The balance tipped in favorof these diseases when people started selecting forparthenocarpic plants. (These plants do not need to be pollinatedto produce fruits and as a result give seedlessfruits). As the banana was dispersed throughout the wettropics, inevitably most of the disease pathogens accompaniedthe vegetative suckers. As human populations beganto grow large numbers of the same cultivar in a location,pathogens began to attack these bananas (Pearse, 2003).Although the fruit from parthenocarpic banana plants arebetter suited for eating, the lack of genetic diversity andmixing causes the plants to become more susceptible todisease (Koeppel, 2005; Canine, 2005). Over time, differentcultivars appealing to a variety of tastes and uses weregenerated, but at the expense of resistance to diseases andpests. This susceptibility to disease has caused problemsfor the banana in the past and present.The banana industry is important to the economyof a number of countries because it provides both jobsand food for the people but banana production in Asia iscurrently fighting a battle with a new form of an old enemy,Panama disease. Panama disease, also known asFusarium wilt, is a banana disease caused by a soil-bornefungus, Fusarium oxysporum f. sp. cubense, that hascaused significant problems for banana production in thepast (Stover, 1990). Prior to the 1950’s, the bananaexport market in Latin America and the Caribbeanregion was dominated by a cultivar known as ‘GrosMichel’ or “Big Mike”. Panama disease Race 1 wasresponsible for the devastation of these bananaplantations and forced the conversion to cultivars of theCavendish group which possessed resistance to Panamadisease Race 1 (Ploetz, 2005a, 2005b). The funguscurrently attacking banana plantations in Asia, Australiaand the Canary Islands is another form of F. oxysporumf. sp. cubense known as Tropical Race 4 (Fig. 7). Threeof the four races of F. oxysporum f. sp. cubense have beenreported toa t t a c kbananas.The other(Race 3)only attacksheliconias(Ploetz,2005b).7Panama disease Tropical Race 4 is especially damagingsince it attacks all varieties of bananas that Races 1 and 2attacks. In addition it also attacks the Cavendishcultivars which are not affected by Races 1 and 2(Ploetz, 2005b), (Fig. 8). This is especially importantsince the Cavendish cultivars are very widely grown forlocal consumption in a variety of countries. Members ofthe Cavendish group are also grown widely in thebanana exporting regions of the world.The fungus infection begins by penetration into8