Research Article Periclinal chimera technique: new plant breeding approach

Abstract

Plant interspecific periclinal chimeras are a mosaic formed by tissues from two species. They are manipulated here as an efficient plant breeding tool for cassava root yields. In this study, plants synthesized from two chimeras, designated as chimera 2 and chimera 4, were characterized morphologically and cytologically to unravel the origin of their tissue layers (L2 and L3). Root yield of the two chimeras was also evaluated. Chimera 2 that was developed from graft union between Manihot fortalezensis (F) as scion and M. esculenta (E) as rootstock and the same in chimera 4 was developed from grafting triploid cassava cultivar (2n = 54) (C) as scion and M. pohlii (P) (2n = 36) as rootstock. A new method of inducing interspecific chimeras without using hormones was also tested in this study. Five combinations between four cassava cultivars on one side and M. fortalezensis and an interspecific hybrid (M. glaziovii x M. esculenta) on the other side were experimented to determine compatibility between the parents. Wild species always gave L2 and L3, independent of being used as rootstock or scion. L3 is responsible for producing pericycle. Thus, its performance was different in each chimera due to specific epigenetic interaction. Of 48 grafts, it was obtained one chimera giving a percentage of 2.1% that is little lower than using hormones but much efficient to use. Chimera induction efficiency in this investigation was the same when using hormones. Thus, our new, less labor, and more cost-effective technique is as much efficient as hormones and is much potential to employ as an effective plant breeding method boosting cassava root yield.

Genome of a citrus rootstock and global DNA demethylation caused by heterografting

“…This technique has been practiced in agriculture for over 2500 years 1 . Grafting has been widely used in modern production of many horticultural crops and some forest trees, such as citrus 2 , 3 , pear 4 , 5 , grape 6 , cassava 7 , and cedar 8 . Plant grafting is an ancient agricultural practice for propagation of uniform seedlings for commercial fruit species and to avoid a juvenile state, as an adult scion grafted onto a juvenile rootstock will maintain its adult state and ability to bear fruit 9 .…”

Research Article Cassava Periclinal Chimera Vigor: A theory on its origin

“…Periclinal chimera can be synthesized within a very short time compared to several generations of backcrosses needed in classical breeding methods which consume various years of hybridization. Moreover, as shown by authors in the last twelve years, the use of periclinal chimera may enable perpetuate what observed of vigor and consequent high productivity (Gakpetor et al, 2017).…”

“…Very few chimera shoots could be obtained in the past until technique of Nassar and coworkers (Gakpetor et al, 2017) where they grafted by whip method two manihot species noting the buds be cut to half of both stock and graft. This stimulated callus tissue between the two buds from which arises chimera.…”

“…This can be done by chromosome counting (Stewart and Derme, 1979;Sugawara et al, 2002;. This chromosome counting of the roots may shed light on constitucion of the periclinal chimera in case of differences in chromosome number of the two parents (Gakpetor et al, 2017).…”

Production of transgenic periclinal chimeras in pumpkin – a tool for revealing cell fates of L1 meristem

“…Plant chimeras occur occasionally in nature, while many have been artificially synthesized through gene mutation, protoplast culture, and grafting between different species (Binding et al 1987;Chen et al 2006;Wang et al 2010). Because of their distinctive and valuable phenotypes, chimeras have been applied to breeding (Gakpetor et al 2017) and fundamental studies, such as tissue and organ development, origination of adventitious buds, and interactions between different tissues and cells (Marcotrigiano & Bernatzky 1995;Burge et al 2002). Chimeras have genetically different cells in the shoot apical meristem (SAM) that form the plant organs.…”