Seed Quality as Related to Harvest Time in Three Key Perennial Grasses Native to Puna Tussock Rangelands of Peru

Jimy Castro,Roberto Distel,Lucrecia Aguirre,Isabel Marques

doi:10.1155/2021/4346186

Abstract

Seed-based rehabilitation programs represent a primary foundation for rangeland recovery, which requires high-quality seed of key native species. The objective of this research was to determine the seed quality at different harvest times for three key perennial grasses native to puna tussock rangelands of Peru: Festuca dolichophylla, Festuca humilior, and Calamagrostis vicunarum. Seeds of each species were harvested at 21, 28, and 35 days after anthesis and evaluated by standard tests to determine the purity, size, viability, and germinability. On average, the seed purity of the studied species ranged between 23% and 44%, hundred-seed weight between 34 mg and 73 mg, seed viability between 24% and 60%, and the seed germination between 18% and 34% over the harvest dates. The highest seed quality was observed in C. vicunarum. Seed quality parameters of the studied species did not show a consistent variation over the harvest times. Overall, the species studied presented relatively low seed quality; therefore, when using it in rehabilitation programs for rangeland recovery, it is important to carry out a previous cleaning process (to reduce nonviable seeds and inert matter) and to use a sufficient quantity of seed for effective establishment of these key grasses.

Highlights

Rangelands under improper grazing management and overutilization deteriorate to varying degrees around the world [1], negatively affecting the provision of ecosystem services and livelihoods for local communities
Seed purity was similar between H1 (21 days after anthesis) and H3 (35 days after anthesis) and higher than at H2 (28 days after anthesis), whereas it was highest in Cavi, intermediate in Fehu, and lowest in Fedo. e drop in seed purity at H2 may have been due to environmental conditions, temperatures that were too low or too high that affect anthesis and seed development negatively in cool-season grasses, increasing the inert matter [5]
Because the florets differed in the date of origin, they were potentially exposed to different environmental conditions from anthesis to seed maturity but they contributed in different relative proportions according to the harvest time

Summary

Introduction

Rangelands under improper grazing management and overutilization deteriorate to varying degrees around the world [1], negatively affecting the provision of ecosystem services and livelihoods for local communities. There is an urgent need to rehabilitate degraded rangelands, and the seeds of key native species represent a foundation for rehabilitation and restoration programs [2]. Knowledge of the quality of native seeds (purity, viability, and germinability) is decisive for achieving success [3]. E time of harvesting is a primary determinant of the seed quality of native grasses [4]. Seed physiological maturity (defined as the maximum seed dry matter accumulation) and seed water content represent key considerations for identifying the optimum time for seed harvesting [5]. Once seeds reach a maximum dry weight, they undergo an accelerated dehydration phase until a hygroscopic equilibrium is attained and harvest maturity reached [6]

Objectives

Results

Conclusion