Utilizing CRISPR-Cas in Tropical Crop Improvement: A Decision Process for Fitting Genome Engineering to Your Species

Adopting modern gene-editing technologies for trait improvement in agriculture requires important workflow developments, yet these developments are not often discussed. Using tropical crop systems as a case study, we describe a workflow broken down into discrete processes with specific steps and decision points that allow for the practical application of the CRISPR-Cas gene editing platform in a crop of interest. While we present the steps of developing genome-edited plants as sequential, in practice parts can be done in parallel, which are discussed in this perspective. The main processes include 1) understanding the genetic basis of the trait along with having the crop’s genome sequence, 2) testing and optimization of the editing reagents, development of efficient 3) tissue culture and 4) transformation methods, and 5) screening methods to identify edited events with commercial potential. Our goal in this perspective is to help any lab that wishes to implement this powerful, easy-to-use tool in their pipeline, thus aiming to democratize the technology.

Palm Foliage as Pathways of Pathogenic Botryosphaeriaceae Fungi and Host of New Lasiodiplodia Species from Mexico

Tropical palm foliage is increasingly imported to satisfy the steady growing demand in European floristry. This palm foliage presumably carries along diverse fungi whose taxonomic and functional diversity have not been addressed so far. The present study investigated Botryosphaeriaceae fungi associated with the foliage of palm species Chamaedorea elegans, C. metallica, C. seifrizii, Dypsis lutescens and Lodoicea maldivica imported from Mexico. Five species were identified using combined morphological characterisation and multilocus phylogenetic analyses based on ITS, TEF-1α, TUB2 and RPB2. In addition to Endomelanconiopsis endophytica, Lasiodiplodia brasiliensis and L. euphorbicola, two new species, namely, L. lodoiceae sp. nov. and L. mexicanensis sp. nov, are proposed. Apart from E. endophytica, mostly known as endophyte, L. brasiliensis and L. euphorbicola are responsible for different rot diseases and the dieback of important tropical crop plants. In pathogenicity tests on the temperate pome fruits apple (Malus domestica) and pear (Pyrus communis), all six Botryosphaeriaceae species induced necrotic lesions at different degrees of severity, with highest the aggressiveness from L. euphorbicola and L. mexicanensis on apple and from L. mexicanensis on pear. The results indicate that tropical palm foliage can be a pathway of potentially pathogenic fungi that may give rise to concerns with regard to plant health in the destination countries.

Relationship between agronomic factors and level of damage by red squirrels to cocoa pods in the Cordillera de Mérida, Venezuela

Cocoa is a tropical crop of great economic and ecological importance, with great potential in Venezuela, where fungal diseases and squirrels, among other factors, affect its productivity. The objective of the work was to analyze the relationship between the level of damage and some agronomic and environmental variables in 39 production of the state of Merida. The types of cocoa present were classified as criollo, forastero and hybrid. The damage percentages were transformed to arcsine and grouped into subjective categories according to the variables; the relationship was statistically analyzed using non-parametric tests: Kruskal-Wallis, Kolmogorov-Smirnov, and Moses, assuming = 0.05. The level of damage was not statistically different (p> 0.05) between the crops located at different altitudes. The same occurred with the variables cocoa lot size, planting density, number of cultivars, level of agrochemicals, type of vegetation surrounding the crop, and distance to the forest. But the level of damage was statistically different (p 0.05) between the production units that differed in the number of associated crops. The level of damage was also statistically different according to the number of shade trees.ha-1 and among those that differed with respect to the presence/absence of alternative fruits. It is concluded that the structural complexity of the crops functions as an integrating element in determining the level of damage caused by squirrels and defines the suitability of their habitat.

A Comparative Evaluation of Trends in Area, Production and Productivity of Cashew in Western and Eastern Regions of India

Cashew is an economically important tropical crop. On average, 52 percent of the raw cashew nut processed in India was imported. In recent years, the decreased supply of raw cashew nuts and increased demand for processing forced the cashew sector to concentrate on increased domestic production. To understand the area, production and productivity scenario of cashew nut; India was divided into eastern and western regions based on the traditional area of cashew cultivation along the coasts. The growth in the area under cashew and production of cashew nuts were examined from 2000-01 to 2017-18. Compound Annual Growth rate of area for eastern and western regions was 2.98 and 1.06 percent respectively. The growth rate of production was calculated as 2.08, and 3.55 percent and productivity growth were calculated to be 2.98 and 1.06 percent for eastern and western regions, respectively. The overall average productivity of different varieties in the western and eastern regions was 16.08 and 10.83 kilograms per tree.

Design and Development of Double Rotor Drum Shredding Machine for Managing Pineapple Residue in Peat Soil

In Malaysia, Pineapple is a one of tropical crop that contributes in generating Malaysian economy. Pineapple is mostly planted on mineral and peat soils, where each has different practices and approaches. In Peat soil condition, nowadays farmers normally managed the pineapple residues by using a chemical to kill and fire to burn before it been replanted. This is common practice to remove the pineapple residues. With this method soil fertility can be affected and open burning will be polluting the environment, as the government nowadays recommending toward green approach.(1) In the 9th Malaysian plan (RMK-9), MARDI has come out with a machine to shred and plough pineapple plant residues back into the soil which are practiced for mineral soil. The machine is adopting a motivator concept. Unfortunately, the machine had the unsatisfied result because the plants were not chopped into small pieces but only separated into a few large parts. (2) In the 11th Malaysian plan (RMK-11), the development of a new concept and prototype with a double rotor drum, design type blade, special blade arrangement and speed gave a promising result in a way to manage the residues of pineapple plants easily without chemical or fire. (3)(4)The objective of the study is based on the design of the machined with double rotor drum shredding that can been conceded as normally rotovator but which has resulted in fine and easy disposal pineapple plant residues.