Potential Biostimulant Effect of Clam Shells on Growth Promotion of Plantain PIF Seedlings (<i>var</i>. Big Ebanga & Batard) and Relation to Black Sigatoka Disease Susceptibility

Abstract

Plantain contributes significantly to income generation and food security for millions of people in the world. However, it faces problems of seedlings quantity, quality and availability. The innovation of the "plants issus de fragments de tiges" (PIF) technique could be a solution to these problems for small holders' farmers. The aim of this research is to evaluate the effect of clam shells through amendment of Batard and Big Ebanga PIF substrate, on the growth promotion of seedlings and their protection against black Sigatoka disease (BSD). Plantain PIF seedlings of the two varieties were grown in a substrate amended with 1% concentration of the clam shells powder in the presence of negative control in the sterile and non-sterile conditions. Agromorphological characteristics, susceptibility level to BSD, total proteins and polyphenols content were assessed. Because of the presence of clam shells in the substrates, explants germinated quickly, generated high number of shoots, grew taller by 32%, with a diameter of pseudo stems of 30%, and area of leaves of 18% compared to control. In addition, the seedlings were less susceptible to BSD by 73% compared to those of controls. The treatment seems to allow the accumulation of larger amounts of total proteins and polyphenols before inoculation and after inoculation that could participate in the growth promotion and the reduction of plant's susceptibility level. Clam shells treatment acts as a biofertilizer/biopesticide and could be helpful to boost production of plantain seedlings, the use of the by-products of fishing in agriculture and helps alleviate poverty of small holders' farmers.

Modelling the response of the PIF plantain seedlings toTithonia diversifoliaand clam shells treatments in the nursery

“…Condition-uSS*Treatment-T5 0,918 0,091 10,090 < 0.0001 0,736 1,100 Height of shoots The day the seedlings were weaned and put in the shade 42 days after weaning in the shade [2] Diameter of shoots The day the seedlings were weaned and put in the shade 42 days after weaning in the shade [2] Area of leaves The day the seedlings were weaned and put in the shade 42 days after weaning in the shade [2,26] BSD severity The day the leaves were inoculated with M. fijiensis 12 days after the inoculation of leaves with M. fijiensis…”

“…The per capita consumption of plantain result in demand 7 largely outstrips supply provoking very high prices for this commodity on rural, urban and 8 trans-border markets. To meet up with this demand, we need to create new plantations in 9 other to improve the performance of this crop whereas, the creation of these new plantations 10 is difficult because of the problem of unavailability of seedlings in quantity, but also seedlings 11 of quality [2]. 12 Vitroplants are considered as the best and safe seedlings but are not affordable for small 13 poor farmers in sub-Saharan Africa.…”

“…However, after about ten years, the PIF has shown some 21 problems limiting its adoption and are now rejected by some farmers. Indeed, many problems 22 are responsible for plants mortality of about 60% during the establishment of new plantations 23 such as contamination on farmlands and the position of the shoot on explants which 24 influences the vigor of the generated plant [2] [4], pest and disease pressure (BSD, banana 25 nematodes and weevil) and declining soil fertility [5]. Indeed, the only control method for 26 BSD in the nursery is leaf removal (deleafing) that seems to be ineffective as seedlings are 27 transplanted to field with 2-4 leaves with high level of black Sigatoka infections, much lower 28 than the recommended 5-6 leaves [6].…”

“…Recent researches have shown that soil amendment with Tithonia diversifolia alone or 32 combine to clam shells, Tithonia diversifolia mulch, Tithonia diversifolia vertical layer and 33 Tithonia diversifolia liquid extract improve the growth promotion of the PIF seedlings, and 1 also protects them efficiently against BSD [2]- [4], [7]-[8]. Hence, these treatments seem to act 2 in the improved PIF seedlings production as a vital stimulator (growth promotion and 3 biofungicide actions).…”

“…The experiments design of this study and the method used are presented in Table 10. 2 The variables (conditions, treatments and stages) and responses (number of shoots, height of 3 shoots, diameter of shoots, area of leaves, BSD severity, total proteins and total polyphenols) 4 were evaluated at the initial stage and at the end stage and presented in Table 11. The number 5 of shoots was count, the height of shoots, diameter of shoots, area of leaves and BSD severity 6 measured, total proteins and total polyphenols quantified as described by [2][3][4]…”