Induction of Earlier Flowering in Cassava through Extended Photoperiod

Marcela Pineda,Tim L Setter,Hernán Ceballos,Juan Cuásquer,Nelson Morante,Sandra Salazar,Peter T Hyde

doi:10.3390/agronomy10091273

Abstract

Erect plant architecture is preferred by farmers but results in late and scarce flowering, which slows down breeding considerably. Inducing earlier and abundant flowering in crossing nurseries (involving erect genotypes) is a key objective for cassava and was the subject of this study. Five genotypes with contrasting flowering behavior were grown under dark night (DN) and extended photoperiod (EP) conditions for three seasons. EP was achieved with different red light emitting diodes (LEDs) with 625–635 nm wavelength all night long or through night-breaks. EP reduced height and number of days to first branching, particularly in non- or late-flowering genotypes. A minimum of 0.02 μmol m−2 s−1 was required to elicit earlier flowering in plants illuminated all night. Early results using five genotypes were validated across 116 genotypes planted in a crossing nursery. EP promoted earlier flowering in erect-plant genotypes but reduced the number of branching events in early flowering genotypes to some extent. 50W LED lamps, fixed at 3 m above ground in a 4.5 m grid, proved to be a practical approach to extend photoperiod in breeding nurseries. Night breaks also proved effective, thus opening the possibility of using solar panels where electricity is not available.

Highlights

Cassava (Manihot escultenta Crantz) is a crop of Neotropical origin and has significant economic relevance, in the lowland tropics
The analysis considers three photoperiod treatments: normal photoperiod (DN), extended photoperiod with low light intensity based on 5LEDs and 10LEDs treatments (EP-L) and extended photoperiod with high light intensity based on 30LEDs and 60LEDs treatments (EP-H)
Results from Experiment 3 indicated that night breaks (NBs) are useful to elicit flowering from plants, Regression analyses of number of branching levels (NBL) on time, similar to those presented at the top of Table 3, were and that light intensity matters when plants are not illuminated all night long

Summary

Introduction

Cassava (Manihot escultenta Crantz) is a crop of Neotropical origin and has significant economic relevance, in the lowland tropics. Its main product is the starchy roots that are harvested, usually, about 12 months after planting. It is a fundamental food security crop in many regions of the world, Sub-Saharan Africa. It is an important industrial crop (the second most important source of starch worldwide) [1]. Farmers harvest cassava 10–12 MAP, at the end of the dry season (or before the cold season in subtropical regions), when root quality would be optimum, and store the stems only for a few weeks until the arrival of the rains (or the warm season in subtropical environments)

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